Opinion
EAGLESON, J.
The issues in this case are: (1) whether the term “unpublished information” in the California newsperson’s shield law (Cal. Const., art. I, § 2, subd. (b); Evid. Code, § 1070) includes a newsperson’s non-confidential, eyewitness observations of an occurrence in a public place; and, (2) if so, whether a newsperson can nevertheless be held in contempt for refusing to disclose such information in a criminal proceeding. [793]*793As we shall explain, we hold the shield law’s broad definition of “unpublished information” does not require a showing by the newsperson that the information was obtained in confidence. We further hold, however, that a newsperson’s protection under the shield law must yield to a criminal defendant’s constitutional right to a fair trial when the newsperson’s refusal to disclose information would unduly infringe on that right. In this case, the trial court correctly determined that the balance between the rights of the newspersons and the defendant weighs in favor of compelled disclosure. We affirm the judgment of the Court of Appeal.
Facts
Underlying Facts
Real parties in interest, Los Angeles Times reporter Roxana Kopetman and photographer Roberto Santiago Bertero, were accompanying members of a Long Beach Police Department task force on patrol. (For convenience we will sometimes refer collectively to Kopetman and Bertero as the reporters.) The officers observed Sean Patrick Delaney and a companion seated on a bench in the Long Beach Plaza Mall. A plastic bag of a type often used to store narcotics was protruding from Delaney’s shirt pocket. The officers inquired about the contents of the bag, and Delaney removed it from his pocket to show that it contained a piece of gold and a piece of jewelry. He told the officers he intended to pawn the items at the mall. Because no pawnshops were in the mall, the officers became suspicious and asked Delaney for his identification. Delaney reached for a jacket lying next to him on the bench as if to get his wallet. According to the officers, they asked Delaney before he picked up the jacket if they could check it for weapons. He allegedly consented to the search. An officer ran his fingers along the outside of the jacket and felt a hard object in its pocket. He reached inside and retrieved a set of brass knuckles, which Delaney claimed was a key chain.
Four days later, the Los Angeles Times (hereafter the Times) published an article about the police task force. The article included information regarding the police contact with Delaney but did not refer to whether he had consented to the search of his jacket pocket.
Procedural History
Delaney was charged in a misdemeanor complaint with possession of brass knuckles in violation of Penal Code section 12020, subdivision (a). He moved to suppress evidence of the brass knuckles, arguing that he had not consented to the patdown search of his jacket and that the resulting seizure [794]*794of the brass knuckles was therefore illegal because the officers had lacked a reasonable suspicion that he was armed. Delaney subpoenaed the reporters to testify at the suppression hearing in municipal court. The reporters moved to quash the subpoenas, contending they could not be compelled to testify because their eyewitness observations of the public search and seizure constituted “unpublished information” protected by the newspersons’ shield law from disclosure. The motions were denied.
Following testimony by the officers at the suppression hearing, the reporters were called to testify by the prosecution to demonstrate the legality of the seizure. Their testimony established that each of them observed the events leading to the seizure and that each was situated in a position to observe whether Delaney had consented to the search of his jacket. The reporters, however, refused to answer any questions relating to whether Delaney had consented. The municipal court concluded that the shield law did not apply to the reporters’ eyewitness observations of the non-confidential, public circumstances of the search and seizure. The court further found that, even if the shield law applied, the need for the reporters’ presumably disinterested testimony on the consent issue outweighed their claim of immunity under the shield law. The court cited both reporters for contempt.
The reporters filed petitions for writs of habeas corpus in the superior court. That court found the shield law provided the reporters with immunity from contempt and granted their petitions.
Delaney and the People of the State of California (through the Long Beach City Prosecutor) filed a joint petition in the Court of Appeal seeking to vacate the orders of the superior court that granted the reporters’ habeas corpus petitions. (Delaney’s misdemeanor prosecution has been suspended pending final resolution of the reporters’ contempt citations.) The Court of Appeal held the shield law does not give a newsperson the right to refuse to testify as to his observations of a public event and ordered the superior court to vacate its orders granting the petitions for writs of habeas corpus. The Court of Appeal’s decision was initially unanimous but, after real parties petitioned for rehearing, one justice changed her position and filed a dissenting opinion.
Discussion
I. History of California's Shield Law
Newspersons had no privilege or immunity under common law to refuse to disclose the identity of their confidential sources. (Ex Parte Lawrence and [795]*795Levings (1897) 116 Cal. 298, 300 [48 P. 124] [upholding contempt citations issued to a newspaper reporter and editor for refusing to disclose confidential sources to the state Senate]; Mitchell v. Superior Court (1984) 37 Cal.3d 268, 274, fn. 3 [208 Cal.Rptr. 152, 690 P.2d 625] [noting prohibition in Evidence Code section 911 of common law privileges]; Tent. Recommendation and Study Relating to the Uniform Rules of Evidence, art. V, Privileges (Feb. 1964) 6 Cal. Law Revision Com. Rep. (1964) p. 488 [noting that “the newsmen’s privilege is entirely alien to the common law”].)1
In 1935 the Legislature passed the first shield law. (Stats. 1935, ch. 532, § 1, pp. 1608-1610.) The statute, which was codified as Code of Civil Procedure section 1881, subdivision 6, provided that newspaper employees could not be adjudged in contempt for refusal to disclose their sources to courts or legislative or administrative bodies. Subsequent amendments extended the immunity to employees of radio and television stations, press associations, and wire services. (Stats. 1961, ch. 629, § 1, pp. 1797-1798.) In 1965 the Legislature transferred these statutory provisions to Evidence Code section 1070, which became effective in 1967. (Stats. 1965, ch. 299, § 2, pp. 1297, 1323-1335; Evid. Code, § 12.)
In 1972, a plurality of the United States Supreme Court concluded that the First Amendment to the federal Constitution does not provide newspersons with even a qualified privilege against appearing before a grand jury and being compelled to answer questions as to either the identity of news sources or information received from those sources. (Branzburg v. Hayes (1972) 408 U.S. 665 [33 L.Ed.2d 626, 92 S.Ct. 2646].) The high court made clear, however, that state legislatures are “free, within First Amendment limits, to fashion their own standards.” (Id., at p. 706.)3
[796]*796In 1974 the California Legislature amended section 1070 to its present form, apparently in response to Branzburg, supra, 408 U.S. 665. (Stats. 1974, ch. 1323, § 1, p.2877; Stats. 1974, ch. 1456, §2, p. 3184.) That amendment expanded the scope of the shield law to protect against the compelled disclosure of “unpublished information” as well as sources.
In June 1980, California voters approved Proposition 5, a state constitutional amendment proposed by the Assembly. (Assem. Const. Amend. No. 4, Stats. 1978 (1977-1978 Reg. Sess.) res. ch. 77, pp. 4819-4820.) The proposition incorporated language virtually identical to section 1070 into the California Constitution, as article I, section 2, subdivision (b).* **4
II. Scope of the Shield Law
Article I, section 2(b) provides that a newsperson “shall not be adjudged in contempt ... for refusing to disclose the source of any information procured while so connected or employed [as a newsperson] ... or for refusing to disclose any unpublished information obtained or prepared in gathering, receiving or processing of information for communication to the public.” (Italics added.)5
Stated more simply, article I, section 2(b) [797]*797protects a newsperson from being adjudged in contempt for refusing to disclose either: (1) unpublished information, or (2) the source of information, whether published or unpublished.* ***6
The parties agree there is no attempt to compel the reporters to reveal the identity of a source. Delaney was the source of whatever information the reporters may have as to whether he consented to the police search of his jacket, and his identity is of course already known.7 Rather, Delaney seeks only the reporters’ testimony as to whether he consented to the search. The reporters do not contend they promised to keep confidential any information they obtained or observations they made while preparing their article on the Long Beach Police Department’s task force. The question therefore is whether the shield law’s definition of “unpublished information” includes a newsperson’s unpublished, nonconfidential eyewitness observations of an occurrence in a public place. We conclude that it does.8
[798]*798A. Language of the shield law
We begin with the fundamental rule that our primary task is to determine the lawmakers’ intent. (Brown v. Kelly Broadcasting Co. (1989) 48 Cal.3d 711, 724 [257 Cal.Rptr. 708, 771 P.2d 406].) In the case of a constitutional provision adopted by the voters, their intent governs. (Kaiser v. Hopkins (1936) 6 Cal.2d 537, 538 [58 P.2d 1278]; Armstrong v. County of San Mateo (1983) 146 Cal.App.3d 597, 618 [194 Cal.Rptr. 294].) To determine intent, “ ‘The court turns first to the words themselves for the answer.’ ” (Brown v. Kelly Broadcasting Co., supra, 48 Cal.3d 711, 724, quoting Moyer v. Workmen’s Comp. Appeals Bd. (1973) 10 Cal.3d 222, 230 [110 Cal.Rptr. 144, 514 P.2d 1224].) “If the language is clear and unambiguous there is no need for construction, nor is it necessary to resort to indicia of the intent of the Legislature (in the case of a statute) or of the voters (in the case of a provision adopted by the voters).” (Lungren v. Deukmejian (1988) 45 Cal.3d 727, 735 [248 Cal.Rptr. 115, 755 P.2d 299].)
The language of article I, section 2(b) is clear and unambiguous as to the question presented in this case. The section states plainly that a newsperson shall not be adjudged in contempt for “refusing to disclose any unpublished information.” (Italics added.) The parties seeking discovery in this case (Delaney and the prosecutor) contend article I, section 2(b) applies only to unpublished information obtained in confidence by a newsperson. Such a construction might be possible if the voters had used the phrase “unpublished information” without the modifier “any.” They did not do so. The use of the word “any” makes clear that article I, section 2(b) applies to all information, regardless of whether it was obtained in confidence. Words used in a constitutional provision “should be given the meaning they bear in ordinary use.” (Lungren v. Deukmejian, supra, 45 Cal.3d 727, 735; Amador Valley Joint Union High Sch. Dist. v. State Bd. of Equalization (1978) 22 Cal.3d 208, 245 [149 Cal. Rptr. 239, 583 P.2d 1281].) In the context of article I, section 2(b), the word “any” means without limit and no matter what kind. (Webster’s New World Diet. (2d college ed. 1982) p. 62.) To restrict the scope of article I, section 2(b) to confidential information would be to read the word “any” out of the section. We decline to do so. Significance should be given, if possible, to every word of an act. [799]*799(Mercer v. Perez (1968) 68 Cal.2d 104, 112 [65 Cal.Rptr. 315, 436 P.2d 315].) Conversely, a construction that renders a word surplusage should be avoided. (City and County of San Francisco v. Farrell (1982) 32 Cal.3d 47, 54 [184 Cal.Rptr. 713, 648 P.2d 935]; California Mfrs. Assn. v. Public Utilities Com. (1979) 24 Cal.3d 836, 844 [157 Cal.Rptr. 676, 598 P.2d 836].)9
We need not rely solely on the voters’ use of the word “any.” Article I, section 2(b) further states: “As used in this subdivision, ‘unpublished information’ includes information not disseminated to the public by the person from whom disclosure is sought, whether or not related information has been disseminated and includes, but is not limited to, all notes, outtakes, photographs, tapes or other data of whatever sort not itself disseminated to the public through a medium of communication, whether or not published information based upon or related to such material has been disseminated.” Nowhere in this broad definition is there an explicit or implied restriction of article I, section 2(b) to confidential information. To so limit the section, we would have to insert into it the word “confidential” and thus violate the cardinal rule that “The constitution is to be interpreted by the language in which it is written, and courts are no more at liberty to add provisions to what is therein declared in definite language than they are to disregard any of its express provisions.” (People v. Campbell (1902) 138 Cal. 11, 15 [70 P. 918]; Ross v. City of Long Beach (1944) 24 Cal.2d 258, 260 [148 P.2d 649].)
Delaney contends a reporter’s percipient observations of a non-confidential occurrence are not “information” within the meaning of shield law. This attempted distinction between observations and information is unpersuasive. Under Delaney’s strained interpretation, a reporter or any other eyewitness to an automobile accident would have no “information” as [800]*800to the accident. This flies in the face of reason and plain English. “Information” includes “reception of knowledge” and “knowledge obtained from reading, observation, or instruction.” (Webster’s New Internal. Diet. (2d ed. 1958) p. 1276, italics added.) When a reporter or other person is called on to testify as to his observations of an event, he is being asked to disclose information. Moreover, if the distinction between observations and information were logical, the result would be that even a newsperson’s confidential observations would not be protected. That result would be contrary to the manifest purpose and language of article I, section 2(b).
In short, the plain language of article I, section 2(b) leads to only one tenable conclusion. We hold that the shield law’s definition of “unpublished information” is not restricted to information obtained in confidence by a newsperson.
B. Legislative and constitutional history
The reporters rely on the legislative history of section 1070 to support their view. Delaney and the prosecutor disagree with the reporters’ interpretation of that history. It is, however, beside the point for two reasons. First, as we have explained, article I, section 2(b) and section 1070 are virtually identical. In light of our determination that the language of article I, section 2(b) is unambiguous, simple logic compels the same conclusion as to the statute. Thus, we need not go beyond the words of the statute to extrinsic aids such as legislative history. (Lungren v. Deukmejian, supra, 45 Cal.3d 727, 735.) To do so would violate the principle that, “When statutory language is thus clear and unambiguous there is no need for construction, and courts should not indulge in it.” (Solberg v. Superior Court (1977) 19 Cal.3d 182, 198 [137 Cal.Rptr. 460, 561 P.2d 1148], italics added.) This rule is deeply rooted in our jurisprudence. (Sturges v. Crowninshield (1819) 17 U.S. 122, 202 [4 L.Ed. 529, 550].)10
Second, in light of the voters’ incorporation of the statutory language into the California Constitution, we need construe only article I, section 2(b).* 11 The legislative history of section 1070 would be [801]*801relevant only if it shed some light on the meaning of its constitutional counterpart, article I, section 2(b). The history, however, is of no help in that regard. Article I, section 2(b) is plain on its face, and we need not— indeed, should not—search for external indicia of the voters’ intent. (Lungren v. Deukmejian, supra, 45 Cal.3d 727, 735.) Moreover, the legislative history of section 1070 could, as a matter of logic, reflect only the Legislature’s intent. That history would not provide us with any guidance as to the voters’ subsequent intent because none of the indicia of the Legislature’s possible intent (committee analysis and digest and letters from the statute’s author) were before the voters. (People v. Castro (1985) 38 Cal.3d 301, 311-312 [211 Cal.Rptr. 719, 696 P.2d 111]; Lungren v. Deukmejian, supra, 45 Cal.3d 727, 742.)12
Delaney also relies on the ballot argument in favor of Proposition 5 in 1980, the measure that created article I, section 2(b). Ballot arguments are accepted sources from which to ascertain the voters’ intent. (In [802]*802re Lance W (1985) 37 Cal.3d 873, 888, fn. 8 [210 Cal.Rptr. 631, 694 P.2d 744]; White v. Davis (1975) 13 Cal.3d 757, 775, fn. 11 [120 Cal.Rptr. 94, 533 P.2d 222].) As with the legislative history of section 1070, however, we need not look beyond the language of the enactment (article I, section 2(b)) when its language is unambiguous. (Lungren v. Deukmejian, supra, 45 Cal. 3d 727, 735.) The ballot argument (unlike the legislative history) is, however, at least relevant to determining the voters’ intent. We therefore consider the ballot argument (set forth in full in the margin) to determine if it demonstrates the voters did not mean what they said.13 The repeated references in the argument to confidentiality and the like permit the inference the proponents of the measure intended to protect only confidential information. The same inference may be drawn from the Legislative Analyst’s statement.14 The inference, however, is far from compelling. The ballot materials emphasized the need for confidentiality but did not state that only confidential matters would be protected. The most reasonable inference is that the proponents chose to emphasize (in the limited space available for ballot arguments) what they perceived as the greatest need. We cannot conclude that, by emphasizing one purpose, perhaps the primary purpose of the measure, the argument misled voters into thinking confidentiality was [803]*803the only purpose, especially when the measure itself made clear that all unpublished information would be protected. Moreover, a possible inference based on the ballot argument is an insufficient basis on which to ignore the unrestricted and unambiguous language of the measure itself. It would be a strained approach to constitutional analysis if we were to give more weight to a possible inference in an extrinsic source (a ballot argument) than to a clear statement in the Constitution itself. We decline to do so.15
C. Prior California decisions
Although the relevant amendment to section 1070 was enacted in 1974 and article I, section 2(b) was adopted in 1980, this court has never determined the substantive scope of either provision.16 The Courts of Appeal, however, have often done so. Initially, the clear majority view in published decisions was that the shield law applies equally to nonconfidential as well as confidential information. (Hammarley v. Superior Court, supra, 89 Cal.App.3d 388, 395-398; Playboy Enterprises, Inc. v. Superior Court, supra, 154 Cal.App.3d 14, 20-22; Hallissy v. Superior Court, supra, 200 Cal.App.3d 1038.) Only one court had restricted the shield law’s application to confidential information. (CBS, Inc. v. Superior Court, supra, 85 Cal.App.3d 241, 250.)
More recently, however, the conflict began to sharpen. In an opinion certified for publication, the Court of Appeal in this case held the shield law applies only to confidential information. Only two weeks earlier, however, a different division of the same district reached a contrary conclusion in an opinion also certified for publication, holding that the shield law protects against the compelled disclosure of any unpublished information, regardless of whether it is confidential. (New York Times Co. v. Superior Court (1988) 215 Cal.App.3d 672 [248 Cal.Rptr. 426], review granted Oct. 27, 1988 (S006709).) We granted review in both cases to resolve the growing conflict. A third Court of Appeal panel thereafter certified for publication an opinion noting the conflict and agreeing with the Court of Appeal decision in this case, holding that a reporter’s eyewitness observations of a public event are [804]*804not protected by the shield law. (Liggett v. Superior Court (1989) 211 Cal.App.3d 1461 [260 Cal.Rptr. 161], review granted Oct. 12, 1989 (SOI 1581).)
In light of the conflict that has emerged, the Court of Appeal decisions provide little clear guidance for our decision, and little would be gained by our reviewing them in detail. We note, however, two general themes that appear in the conflict. As we have done in this case, the courts that have applied the shield law to all information have relied on the explicit language of the shield law. (Playboy Enterprises, Inc. v. Superior Court, supra, 154 Cal.App.3d 14, 20-22; Hammarley v. Superior Court, supra, 89 Cal.App.3d 388, 395-398.)
By contrast, the courts that have restricted the shield law to confidential information have paid insufficient attention to the shield law’s language. For example, in CBS, Inc. v. Superior Court, supra, 85 Cal.App.3d 241, 250, the court seemed to conclude that no purpose would be served by protecting nonconfidential information. The court did not explain how it found in the shield law a purpose to protect only confidential information. In this case and in Liggett v. Superior Court, supra, 211 Cal.App.3d 1461, review granted October 12, 1989 (SOI 1581), the courts relied extensively on the legislative history of section 1070 and the ballot argument for article I, section 2(b). As we have already explained (ante, pp. 800-803), there is no need to resort to extrinsic aids when a provision is unambiguous and, in any event, the ballot argument and legislative history in this case are too equivocal to overcome the clear definition of “unpublished information” in article I, section 2(b)’s language. We disapprove of those Court of Appeal decisions that hold or suggest the shield law protects only confidential information.
D. Public policy
The parties correctly approach this case as being one of application of a specific constitutional provision. Implicit in their respective arguments, however, are conflicting notions as to appropriate public policy in protecting a newsperson’s unpublished information. We need not consider this issue. As we have explained, article I, section 2(b) contains an unambiguous definition of “unpublished information.” It is bedrock law that if “the law-maker gives us an express definition, we must take it as we find it . . . .” (Bird v. Dennison (1857) 7 Cal. 297, 307.) “[C]ourts, in construing the constitution, are bound to suppose that any inconveniences involved in the application of its provisions, according to their plain terms and import, were considered in its formation, and voluntarily accepted as less intolerable than those which are thereby avoided, or as fully compensated by countervailing advantages.” (People v. Pendegast (1892) 96 Cal. 289, [805]*805294 [31 P. 103]; Sturges v. Crowninshield, supra, 17 U.S. 122, 202 [4 L.Ed. 529, 550].) Our proper function is not to judge the wisdom of article I, section 2(b) or the way in which it is written.
E. Conclusion as to scope of shield law
We hold that article I, section 2(b) is not contingent on a showing that a newsperson’s unpublished information was obtained in confidence. Article I, section 2(b)’s definition of “unpublished information” includes a newsperson’s nonconfidential, eyewitness observations of an occurrence in a public place.17
III. Delaney’s Constitutional Rights
Our determination that the reporters’ observations of the police search are “unpublished information” within the scope of article I, section 2(b) does not decide the issue of whether the municipal court properly held the reporters in contempt for refusing to disclose that information. The reporters themselves concede, as they must, that the shield law’s protection is overcome in a criminal proceeding on a showing that nondisclosure would deprive the defendant of his federal constitutional right to a fair trial. Although this court has not decided a case involving the application of the shield law in a criminal prosecution, the principle is beyond question. (CBS, Inc. v. Superior Court, supra, 85 Cal.App.3d 241, 251; Hallissy v. Superior Court, supra, 200 Cal.App.3d 1038; Playboy Enterprises, Inc. v. Superior Court, supra, 154 Cal.App.3d 14, 24-25; Hammarley v. Superior Court, supra, 89 Cal.App.3d 388, 402; cf. People v. Borunda (1974) 11 Cal.3d 523, 527 [113 Cal.Rptr. 825, 522 P.2d 1] [defendant seeking identity of anonymous informant].)18 The incorporation of the shield law into the California [806]*806Constitution cannot restrict a criminal defendant’s federal constitutional right to a fair trial. (Mulkey v. Reliman (1966) 64 Cal.2d 529, 533 [50 Cal.Rptr. 881, 413 P.2d 825], affd. (1967) 387 U.S. 369 [18 L.Ed.2d 830, 87 S.Ct. 1627] [explaining that California constitutional amendment adopted by ballot must conform to the United States Constitution].) Such result would violate the supremacy clauses of the federal and state Constitutions. (U.S. Const., art. VI, cl. 2; Cal. Const., art. III, § 1; Hammarley v. Superior Court, supra, 89 Cal.App.3d 388, 399, fn. 4.)19
The parties disagree, however, as to the nature of the showing a criminal defendant must make to overcome a claim of immunity under the shield law.20 Delaney contends he need establish only a reasonable possibility that the evidence sought to be discovered might result in his exoneration. The reporters propose a more complex, four-part test under which a defendant would have to show the following: (1) The information must go to the heart of defendant’s case. (2) The information must have a significant effect on the outcome of the case. (This proposed element seems to be the same as the “heart-of-the-case” element.) (3) The information is not available from alternative sources. (4) The infringement on the defendant’s rights caused by nondisclosure must outweigh the newsperson’s interests. (This element seems to be the conclusion a court would reach under the test rather than an element of the test.) As we will [807]*807explain, precedent and principle lead us to conclude that neither test is entirely warranted.
A. The proper test for accommodating conflicting constitutional rights
To formulate the proper test we begin with our decision in Mitchell v. Superior Court, supra, 37 Cal.3d 268, in which we set forth a balancing test to determine when a reporter must disclose confidential information. We identified four relevant factors for a trial court to consider when making that determination. First, we noted the nature of the proceeding and observed that, “In general, disclosure is appropriate in civil cases, especially when a reporter is a party to the litigation.” (Id., at p. 279.) Second, the Mitchell court stated the information must be more than merely relevant and that it must go to “the heart of the case” for the party seeking discovery. (Id., at pp. 280-282.) Third, the court stated that discovery should generally be denied unless it is shown that all alternative sources of the information have been exhausted. (Id., at p. 282.) Fourth, Mitchell stated that the trial court should consider the importance of protecting confidentiality in the case at hand. (Id., at pp. 282-283.)
Although Mitchell, a defamation action, helps to illustrate the competing concerns that arise when a litigant seeks information from a newsperson, an identical approach is not entirely appropriate in a criminal proceeding. We were careful to emphasize in Mitchell that “In criminal proceedings, both the interest of the state in law enforcement, recognized as a compelling interest in Branzburg (see 408 U.S. 665, 700 [33 L.Ed.2d 626, 650]), and the interest of the defendant in discovering exonerating evidence outweigh any interest asserted in ordinary civil litigation.” (Mitchell, supra, 37 Cal.3d at p. 278.) We did not consider the factors a court should consider in a criminal case.
1. Threshold showing required
In now deciding the issue, we must first consider the threshold showing a criminal defendant must make. The reporters claim Delaney must show their testimony would go to the “heart of his case.” He contends he need show only a reasonable possibility the evidence might result in his exoneration. On this point, Delaney has the better view. In CBS, Inc. v. Superior Court, supra, 85 Cal.App.3d 241, the court explained, “Against this right [of a free press] we are obliged to measure the threat to defendants’ right to a fair trial. The existence of such a right is clear .... [I]t has resulted in the rule that, where a criminal defendant has demonstrated a reasonable possibility that evidence sought to be discovered might result in his exonera[808]*808tion, he is entitled to its discovery.” (Id., at p. 251, italics in original; Hallissy v. Superior Court, supra, 200 Cal.App.3d 1038, 1045.) Similarly, in Hammarley v. Superior Court, supra, 89 Cal.App.3d 388, the court stated, “ ‘Allowing an accused the right to discover is based on the fundamental proposition that he is entitled to a fair trial and an intelligent defense in light of all relevant and reasonably accessible information.’ ” (Id., at pp. 398-399, quoting Pitchess v. Superior Court (1974) 11 Cal.3d 531, 535 [113 Cal.Rptr. 897, 522 P.2d 305], italics added.)
We hold that, to overcome a prima facie showing by a newsperson that he is entitled to withhold information under the shield law, a criminal defendant must show a reasonable possibility the information will materially assist his defense. A criminal defendant is not required to show that the information goes to the heart of his case.21
A criminal defendant’s constitutional right to compulsory process was intended to permit him to request governmental assistance in obtaining likely helpful evidence, not just evidence that he can show beforehand will go to the heart of his case. “The need to develop all relevant facts in the adversary system is both fundamental and comprehensive. The ends of criminal justice would be defeated if judgments were to be founded on a partial or speculative presentation of the facts. The very integrity of the judicial system and public confidence in the system depend on full disclosure of all the facts, within the framework of the rules of evidence.” (United States v. Nixon (1974) 418 U.S. 683, 709 [41 L.Ed.2d 1039, 1064, 94 S.Ct. 3090], italics added [claim of presidential privilege].)22
The “reasonable possibility” requirement is also far more workable than the “heart of the case” test proposed by the reporters. It would be impracti[809]*809cal to require a trial court to attempt to divine whether the evidence sought from the newsperson would cause a jury to exonerate a criminal defendant. A court cannot be expected to have that degree of prescience. Moreover, if applied literally, the “heart of the case” requirement would allow a defendant to obtain only evidence that would support a directed verdict in his favor.
To provide guidance to the trial courts, we believe it helpful to make clear how the threshold requirement must be applied in practice. First, the burden is on the criminal defendant to make the required showing. (Hallissy v. Superior Court, supra, 200 Cal.App.3d 1038, 1045.) Second, the defendant’s showing need not be detailed or specific, but it must rest on more than mere speculation. Third, the defendant need not show a reasonable possibility the information will lead to his exoneration. He need show only a reasonable possibility the information will materially assist his defense. The distinction between exoneration and assisting the defense is significant. “Exoneration” means “the removal of a burden, charge, responsibility, or duty.” (Black’s Law Diet. (5th ed. 1979) p. 516, col. 2.) Stated more simply, in criminal proceedings, “exoneration” is generally understood to mean an acquittal or dismissal of charges. Evidence, however, may be critical to a defense even if it will not lead to exoneration. For example, evidence may establish an “imperfect defense,” a lesser included offense, a lesser related offense, or a lesser degree of the same crime; impeach the credibility of a prosecution witness; or, as in capital cases, establish mitigating circumstances relevant to the penalty determination. A criminal defendant’s constitutional right to a fair trial includes these aspects of his defense.23
2. Factors to consider
By meeting the threshold requirement, a defendant is not necessarily entitled to a newsperson’s unpublished information. The trial court must then consider the importance of protecting the unpublished information. (Mitchell, supra, 37 Cal.3d at pp. 282-283.) This determination may properly be characterized as a balancing of the defendant’s and newsperson’s respective, perhaps conflicting, interests.24 The factors to be considered in making this determination are as follows:
[810]*810(a) Whether the unpublished information is confidential or sensitive
If the information is not confidential, the court should consider whether it is nevertheless sensitive, that is, whether its disclosure would somehow unduly restrict the newsperson’s access to future sources and information. (We hereafter refer to this type of nonconfidential information as “sensitive information.”)25 Generally, nonconfidential or nonsensitive information will be less worthy of protection than confidential or sensitive information. Disclosure of the latter types of information will more likely have a significant effect on the newsperson’s future ability to gather news. (U.S. v. LaRouche Campaign (1st Cir. 1988) 841 F.2d 1176, 1180-1182 [noting slight deference due nonconfidential information].) The protection of that ability is the primary purpose of the shield law. (Ballot Pamp., Proposed Amends, to Cal. Const, with arguments to voters, Primary Elec., supra, p. 19; see ante, at p. 802, fn. 13.)26
(b) The interests sought to be protected by the shield law
Even if the information was sensitive or obtained in confidence, other circumstances may, as a practical matter, render moot the need to avoid disclosure. If, as in this case, the criminal defendant seeking disclosure is himself the source of the information, it cannot be seriously argued that the source (the defendant) will feel that his confidence has been breached.27 The [811]*811reporter’s news-gathering ability will not be prejudiced. Other circumstances may also mitigate or eliminate the adverse consequences of disclosure. We do not purport to decide the significance to be given to any future set of facts before a trial court. The point is simply that a trial court must determine whether the policy of the shield law will in fact be thwarted by disclosure.
(c) The importance of the information to the criminal defendant
A defendant in a given case may be able not only to meet but to exceed the threshold “reasonable possibility” requirement. For example, he may be able to show that the evidence would be dispositive in his favor, i.e., to use the reporters’ phrase, that it goes to “the heart of defendant’s case.” If so, the balance will weigh more heavily in favor of disclosure than if he could show only a reasonable possibility the evidence would assist his defense.
(d) Whether there is an alternative source for the unpublished information
We stated in Mitchell, supra, 37 Cal.3d 268, 282, that discovery of a reporter’s confidential information should be denied unless the party seeking it “has exhausted all alternative sources of obtaining the needed information.” This requirement has also been imposed on criminal defendants. (Hammarley v. Superior Court, supra, 89 Cal.App.3d 388, 399; Hallissy v. Superior Court, supra, 200 Cal.App.3d 1038, 1045-1046.) Whether there is an alternative source is indeed a factor for the trial court to consider in a criminal proceeding. In light of a defendant’s constitutional right to a fair trial, however, Mitchell, a civil case, does not mandate a rigid alternative-source requirement in criminal proceedings.
The facts in Mitchell, supra, 37 Cal.3d 268, also suggest the alternative-source requirement may not always be appropriate. In Mitchell, the plaintiff sought documents that would reveal confidential sources of information. (Id., at p. 272.)28 The obvious purpose of the alternative-source requirement [812]*812is to protect against unnecessary disclosure of a newsperson’s confidential or sensitive information. Where the information is shown to be not confidential or sensitive, the primary basis for the requirement is not present and imposing a rigid requirement would be to sustain a rule without a reason. As we have explained above, the proper balancing in a criminal case must take into account whether the unpublished information is confidential or sensitive and, if so, the importance of protecting the information in a given case. (Ante, at pp. 810-811.) For the same reason, a trial court should consider the nature of the information in determining whether to impose an absolute alternative-source requirement in a given case.
We also note that in Mitchell, supra, 37 Cal.3d 268, the information request was for documents that would reveal the identity of possible witnesses. We noted that the names of these persons likely could be obtained from sources other than the newsperson. Objective evidence of that nature is likely unaffected by its source. The contents of a document do not depend on the source of the document (assuming no alteration). Similarly, the name of a witness is the same regardless of who provides the name. The evidence sought by Delaney in this case, however, is qualitatively different from that sought in Mitchell. Delaney seeks the reporters’ testimony as to their percipient observations of the events leading to his search and arrest. Two witnesses to an act may—indeed, likely do—see it differently, and even when their perceptions are substantially the same, their recollection of the event may differ. Moreover, even if their testimony is substantively similar, one witness may have more credibility with a jury. Likewise, two witnesses may convince the jury of a fact where one witness by himself would not do so.
Finally, we note a significant practical difference between this case and Mitchell, supra, 37 Cal.3d 268. That case arose out of a pretrial discovery order in a civil case. In light of the wide range of procedures available for pretrial discovery in civil litigation, it is not unreasonable to require a party seeking information from a newsperson to look elsewhere first. There are no similar procedures available to a criminal defendant. For example, he cannot compel a witness’s attendance at a deposition and, if unsuccessful in obtaining information, subpoena a different witness. Moreover, the economic reality of the criminal justice system is such that a criminal defendant will generally have less opportunity than a civil litigant to obtain information before trial.
For all the foregoing reasons, we conclude that a universal and inflexible alternative-source requirement is inappropriate in a criminal proceeding. In considering whether the requirement is appropriate in a given case, the trial court should consider the type of information being sought [813]*813(e.g., names of potential witnesses, documents, a reporter’s eyewitness observations), the quality of the alternative source, and the practicality of obtaining the information from the alternative source. The trial court must also consider the other balancing factors set forth above: whether the information is confidential or sensitive, the interests sought to be protected by the shield law, and the importance of the information to the criminal defendant. In short, whether an alternative-source requirement applies will depend on the facts of each case.29
3. Balancing the factors
Although a trial court must consider the foregoing factors, their relative importance will likely vary from case to case. In some cases, as in the present one, all the factors may weigh strongly in favor of disclosure. In others, the balance may be more even, and in some cases one factor may be so compelling as to outweigh all the others. We decline to hold in the abstract that any factor or combination of factors must be determinative. A mechanistic, checklist approach would not in the long run (nor perhaps even in a particular case) serve the best interests of either newspersons or criminal defendants.
4. Whether an in camera hearing is required
The reporters contend an in camera hearing must be held in every case before a newsperson can be forced to disclose unpublished information. The contention is overbroad. The purpose of an in camera hearing is to protect against unnecessary disclosure of confidential or sensitive information. The reporters fail to explain what purpose an in camera hearing would serve when the information, as in this case, is admittedly not confidential or sensitive.30 In the cases cited by the reporters, the information was at least arguably confidential. For example, in CBS, Inc. v. Superior Court, supra, 85 Cal.App.3d 241, the Court of Appeal remanded to the trial court for an in camera hearing but noted the newspersons’ “claimed pledge of secrecy.” (Id., at p. 254.) The reporters’ reliance on Hammarley v. Superior Court, supra, 89 Cal.App.3d 388, in which the court affirmed a contempt judgment, is even more misplaced. In Hammarley, the newsperson argued that the shield law immunity was absolute and that an in camera hearing should [814]*814not have been allowed. The Court of Appeal concluded to the contrary. (Id., at pp. 402-403.) The decision in no way supports the view that an in camera hearing is required in every case.31
When a criminal defendant, however, seeks confidential or sensitive information, the practical need for an in camera hearing is obvious. The shield law would be illusory if a reporter had to publicly disclose confidential or sensitive information in order for a court to determine whether it should remain confidential or sensitive. We emphasize, however, that a trial court need not waste its valuable resources for an in camera hearing based on a specious claim of confidentiality or sensitivity.32 The court has discretion in the first instance to determine whether a newsperson’s claim of confidentiality or sensitivity is colorable. If the court determines the claim is colorable, it must then receive the newsperson’s testimony in camera.
B. Application of the proper test to this case
Under the proper balancing test set forth above, Delaney was clearly entitled to the reporters’ testimony as to whether he consented to the police search of his jacket.
Threshold showing—Even under the test advocated by the reporters (heart of the case), Delaney would be entitled to their testimony. The municipal court explained to the reporters’ counsel the lack of probable cause for the search: “If there were probable cause for the search, I guarantee you the prosecutor would not be introducing the matter of [Delaney’s] consent.” The court explained that if there was no consent the search was therefore illegal, and the charge against Delaney would have to be dismissed. Conversely, if he consented to the search, it was legal, the brass knuckles would be admitted into evidence, and Delaney would have little chance of an acquittal. As the court put it, the case “will rise or fall on the admission or not of those metal knuckles.” We agree. It is an understatement to say, in the words of the test we adopt, that there is a reasonable [815]*815possibility the reporters’ testimony will assist Delaney in his defense. There is a substantial certainty that the reporters’ testimony will materially affect the outcome of the criminal proceeding. Delaney has met and surpassed the required threshold showing.
Balancing factors—The balance weighs overwhelmingly in favor of requiring the reporters to testify. A brief review of the factors to be balanced makes this clear.
(1) Whether the unpublished information is confidential or senstitive—As we have already noted, the reporters do not claim their percipient observations of Delaney’s search and arrest in a public place were made in confidence or were sensitive.
(2) The interests sought to be protected by the shield law—There is not even a suggestion in this case that the reporters’ testimony would impinge on their future news-gathering ability or other interest, if any, sought to be protected by the shield law. Both parties who were observed by the reporters (Delaney and the police) are seeking their testimony. Thus, it cannot be said the parties or anyone else would be reluctant to provide these reporters with future information based on a belief that the reporters had breached a confidence or divulged sensitive information.
(3) The importance of the information to the criminal defendant—As explained above, the reporters’ testimony will likely be determinative of the outcome of this case.
(4) Whether there is an alternative source for the unpublished information—We have explained that a criminal defendant need not always show the lack of an alternative source for a newsperson’s unpublished information. We need not consider whether such a showing was required in this case because the municipal court implicitly assumed that it was required, and Delaney made a satisfactory showing. At the hearing on the motion to suppress, the reporters’ counsel suggested that Delaney be required to take the stand and testify as to whether he had consented to the search. The court promptly advised counsel as to a defendant’s constitutional right not to do so.33 Counsel also urged as alternative sources Delaney’s companion, who was present at the time of the search, and four other officers who might have been within hearing distance of the search. The court correctly explained that neither the companion nor the other officers would be disinterested witnesses. The only two persons fitting that description are the two [816]*816reporters. Thus, contrary to their assertion, their testimony would not be merely cumulative to that of the other potential witnesses. We concur in the municipal court’s determination that there was no meaningful alternative source for the reporters’ testimony.
In short, the court struck the correct balance. Delaney’s personal liberty is at stake. The reporters are not being asked to breach a confidence or to disclose sensitive information that would in any way even remotely restrict their news-gathering ability. All that is being required of them is to accept the civic responsibility imposed on all persons who witness alleged criminal conduct.
C. Standard of appellate review
Finally, the reporters contend almost in passing that we are not bound by the municipal court’s decision, which they characterize as being comprised of legal conclusions rather than factual findings. The reporters attack the decision on two grounds. First, they contend it is not supported by substantial evidence. We disagree. We have reviewed the record and, as set forth above, we find the municipal court’s decision to be amply supported.
Second, the reporters contend we are required to exercise our independent judgment as to the correctness of the municipal court’s order of contempt because important constitutional interests are at stake. Apparently, the reporters would have us hold that independent appellate judgment is mandated in all cases under the shield law. Article I, section 2(b) makes no provision for such a standard of review. Nor do the reporters cite authority from any jurisdiction requiring such review under a shield law. We need not and do not decide the issue, however, because, as noted above, we have reviewed the record, and we independently conclude without difficulty that it fully supports the municipal court’s thoughtful decision.34
[817]*817Disposition
The judgment of the Court of Appeal is affirmed. The Court of Appeal is directed to issue a peremptory writ of mandate compelling respondent Los Angeles Superior Court: (1) to vacate its orders entered December 16, 1987, in case numbers HC 206320 and HC 206321, entitled In re Roxana Kopetman and In re Roberto Santiago Bertero, respectively, which orders granted their petitions for writs of habeas corpus; and (2) to simultaneously make new and different orders denying the petitions for writs of habeas corpus.
Lucas, C. J. (as to part III), Panelli, J., Kennard, J., and Kremer (Daniel J.), J.,* concurred.
Presiding Justice, Court of Appeal, Fourth Appellate District, Division One, assigned by the Chairperson of the Judicial Council.