Mr. Justice Rutledge
delivered the opinion of the Court.
This case, like Fishgold v. Sullivan Drydock & Repair Corp., 328 U. S. 275, presents a problem in the seniority standing of a reemployed veteran. It arises under § 8 of the Selective Training and Service Act of 1940.1 The Fishgold case held that under the Act a veteran is entitled to be restored to his former position plus seniority which would have accumulated but for his induction into the armed forces.2 Here the question concerns the duration of the veteran’s restored statutory seniority standing. The petitioners maintain that it ends with the first year of his reemployment. Respondent’s position is that it [42]*42lasts as long as the employment continues.3 A suggestion has also been made that occurrences taking place since the decision in the Circuit Court of Appeals may have rendered the cause moot.
The case is an aftermath of a general controversy over seniority rights which arose among the employees of two corporations following their consolidation on January 1, 1944. Because of the relation of the general controversy to this litigation a detailed statement of the facts becomes necessary. Prior to their consolidation the Highland Body Manufacturing Company had been a wholly owned subsidiary of the petitioner, the Trailmobile Company. The two corporations manufactured the same commodities in separate plants in Cincinnati, Ohio.4 During 1943 under the plan of consolidation the supplies, equipment and personnel of Highland were transferred gradually to the plant of Trailmobile. It took over the assets and business of Highland and assumed all its obligations. The employees of Highland were transferred to the payroll of Trailmobile as of January 1, 1944, when the consolidation became fully effective.5
[43]*43The employees of both companies had been affiliated with the American Federation of Labor. 51 N. L. R. B. 1106, 1108. At the time of the consolidation the Highland group, including respondent, claimed seniority with Trailmobile as of the dates of their employment by Highland. The former Trailmobile employees opposed this, maintaining that the Highland personnel should be considered as new employees of Trailmobile, with seniority dating only from January 1, 1944. This dispute was submitted to national representatives of the A. F. of L. They decided in favor of the Highland group.
The former Trailmobile employees were dissatisfied with this decision. They outnumbered the Highland claimants about ten to one. Accordingly, reorganizing as a unit of the Congress of Industrial Organizations, they requested recognition as the exclusive bargaining agent of Trailmobile’s employees, including the Highland transferees. An election was held under the auspices of the National Labor Relations Board, in which the new C. I. 0. local was chosen as bargaining representative for a unit composed of both groups.6
Trailmobile accordingly negotiated with the C. I. 0. and in July, 1944, a collective bargaining agreement was concluded, effective as of June 21,1944. It provided that the seniority rights of former Highland employees should be fixed as of January 1, 1944, regardless of the dates of their original employment by Highland.
Respondent Whirls had been in Highland’s employ from 1935 to 1942, when he entered military service. He was [44]*44honorably discharged and returned to his work with Highland in May, 1943.7 He was thus among the employees transferred from Highland to Trailmobile as of January 1, 1944, whose seniority was reduced so as to start as of that date by the July, 1944, collective agreement with the C.I.O.
The Highland group contested the agreement’s validity in the Ohio courts in a class suit brought July 17, 1944, by Hess, one of their number, on behalf of himself and 178 others similarly situated. These included 104 persons actually at work, veterans and nonveterans, among whom was Whirls, and 74 employees then in the armed forces. The petition alleged that Trailmobile then had about 500 employees in military service, of whom apparently some 426 were outside the Highland group.
The theory of the class suit was that, although the plaintiffs were not then members of the C. I. 0., the collective bargaining agent was the representative of all employees in the unit and hence could not legally deprive a minority of the employees which it represented of their accrued seniority and other rights by any collective agreement with the company.8 The petition alleged that the collective agreement arbitrarily and unlawfully deprived the plaintiffs of their “vested individual rights” and asked mandatory injunctive relief restoring each to seniority status as of the date of his employment by [45]*45Highland. The company and the collective agent stood upon the terms of the collective agreement and the agent’s authority as certified representative to make it as justifying the action taken under it.
The Ohio courts held against the plaintiffs in the action, sustaining the position of the company and the union.9 They held in effect that the seniority rights in issue arose exclusively from contract, making no reference whatever to § 8 of the Selective Training and Service Act or any question relating to it;10 that the company and the collective representative were lawfully empowered to enter into the contract fixing those rights as of January 1,1944; that the trial court was not authorized, in its own language, “to contract for the plaintiff[s] or make a new contract,” since that powder “exists only in the exclusive bargaining agent, under the provisions of the National Labor Act so long as that agent acts within the law.” 11
Accordingly the suit was dismissed. The record here does not disclose the date of the trial court’s judgment. But its decision was affirmed by the Ohio Court of Appeals before October 2, 1945, when the union’s answer was filed in the present cause; and the case had been finally determined against the plaintiff’s claims by the Supreme Court of Ohio prior to October 15, 1945.12
The record is not entirely clear concerning the exact character and sequence of events between July 15, 1944, [46]*46when Whirls and other former Highland employees were notified that their seniority status would be changed, and September 18, 1945, when the present suit was filed in the District Court. Apparently, after the notice was given, Selective Service officials intervened in behalf of Whirls and other veterans,13 although his allegation that his seniority was restored as a result of that intervention was denied both by the company and by the union. There is ambiguity also concerning whether the closed-shop provision appeared in the 1944 agreement or only in the 1945 one between the company and the C. I. 0. The facts of record, however, are more consistent with the view that it was not introduced until the latter year.
At any rate, in June or July, 1945, Whirls joined the C. I. 0. union, thus complying with the closed-shop provisions of the collective agreement. And until about September 3 of that year he continued to be employed in the painting department, where he had the highest seniority and was drawing pay of $1.05 per hour. On or about that date, however, the company transferred him to the stock department, threatening to reduce his pay to $0.83 per hour and also to reduce his seniority rating in accordance with the collective agreement.
Whether or not the threatened reductions actually took effect is not clear from the record, for not long afterward Whirls was transferred again, to a position paying $1.18 per hour in another department. But before this was done, represented by the United States [47]*47Attorney,14 he brought this suit in the District Court under the Selective Training and Service Act. He sought to enjoin the threatened decrease in pay and change in seniority status. He also asked for restoration to his former position in the painting department and to his seniority as fixed by his original employment with Highland. The employer answered and the local C. I. 0. union intervened in support of the employer’s position. However, since Whirls had been transferred again before the case came on for hearing, the parties agreed at the hearing to limit the issues to those affecting the question of seniority. This was presented in two forms, (1) on the merits, the facts being substantially stipulated; (2) on the question whether the state court proceeding in the class suit had determined the seniority rights of Whirls, making the issue now raised res judicata for this suit. See Angel v. Bullington, 330 U. S. 183.
Taking respondent’s view in both respects, the District Court rendered judgment in his favor. The Circuit Court of Appeals for the Sixth Circuit affirmed the District Court’s judgment. 154 F. 2d 866. Besides holding res judicata inapplicable, both courts took the view, contrary to that later reached here in the Fishgold case, that the reemployed veteran was entitled to “superseniority” for one year following his reemployment,15 and went on to hold that his statutory preferred status with respect to seniority and other incidents of his employment did not end with the expiration of that year. Because of the bear[48]*48ing of the Fishgold decision upon the problem and the importance of the question presented, we granted certiorari. 328 U. S. 831.
I.
At the outset it is important, in view of certain questions which have been injected beyond the issues presented for decision, to state explicitly what is not before us. In the first place, we are not required to determine whether the class suit in the state courts constituted an adjudication of the rights of the parties involved in this litigation. That question was presented to the District Court and the Circuit Court of Appeals. Both determined it adversely to petitioners, but no error was assigned to this ruling in the petition for certiorari. The question is therefore not before this Court and we express no opinion concerning it.
The view entertained in this respect by the District Court and the Circuit Court of Appeals, however, has assumed tangental bearing in connection with the suggestion that the cause may have become moot. In its memorandum filed upon the application for certiorari and in its brief, the Government calls attention to certain events not appearing of record but taking ¡olace after the decision of the Court of Appeals. Though suggesting the facts for our attention, the Government maintains that they do not render the controversy moot. This Court, of course, does not render advisory opinions. And since the suggestion of the facts not only is sufficient to raise the question of mootness but has injected others not comprehended in the issues, it is necessary to dispose of the matter before undertaking a determination of the question otherwise properly here for decision.
It is suggested and not denied that under date of April 10, 1946, respondent was notified by the collective agent that he had been charged with conduct unbecoming a [49]*49member of the union, namely, in bringing this suit without exhausting the remedies provided by its constitution and by-laws; in thereby violating the collective agreement; in negotiating with the employer through others than the union; and in conducting himself in a manner harmful to its interests and those of its members. Accordingly, on April 15,1946, the union requested Trailmobile to suspend Whirls from work. In consequence, the company directed him not to report for duty. Since then, however, it has continued to keep him on the payroll, on leave of absence with full pay. Although the Government urges that Whirls thus continues in the company’s employ and consequently the case is not moot, its suggestion of the facts has overlaid the only issue brought here by the petition for certiorari with questions of unlawful discrimination allegedly arising out of the suggested facts, under the decisions in Steele v. Louisville & Nashville R. Co., 323 U. S. 192; Tunstall v. Brotherhood of Locomotive Firemen and Enginemen, 323 U. S. 210; and Wallace Corp. v. National Labor Relations Board, 323 U. S. 248.16
The facts thus put forward have no proper bearing in this case otherwise than to suggest the question of mootness and to require that any decision which is made upon the merits here be made without prejudice to the future assertion of any rights of respondent which may have been violated by the conduct set forth. We agree that in the circumstances related he remains an employee of the company and the cause is not moot.
[50]*50We also agree that the question of unlawful discrimination is not properly before us for decision.17 That question, insofar as it arose from events prior to this litigation, was involved in the Ohio class suit without reference, it would seem, to § 8 or its possible effects. And because the petition for certiorari, as we have noted, assigned no error to the Court of Appeals’ ruling on the issue of res judicata arising from the outcome of the class suit, we are not at liberty now to consider the effect of that litigation or the issues of discrimination embraced in it. Insofar as any question of unlawful discrimination may be thought to arise from the facts said to have taken place after the decision of the Circuit Court of Appeals, we are also not free at this time to consider or determine such an issue. As the brief of the Government in respondent’s behalf pertinently states, “These points were not raised on respondent’s behalf in .the lower courts, and no evidence was introduced by any party on the issue of unfair discrimination. Cf. Hormel v. Helvering, 312 U. S. 552, 556. In view of that fact, and of the Hess litigation, we believe that it would be inappropriate, at this stage, to argue these issues.”
Wholly aside from any question of power, this disclaimer on behalf of the party affected is a sufficient reason to justify refusal to inject such an issue here or to volunteer aid not sought. We therefore are required to say no more concerning the matter now than that, if respondent has been unlawfully expelled, suspended or otherwise dealt with by the union for asserting his legal rights, the law has provided remedies for such injuries and they may be redressed in appropriate proceedings designed for that purpose upon proof of the facts constituting the wrong and due consideration of the legal issues they present. To assure this possibility, however, the remand which be[51]*51comes necessary in this cause on the merits will be so framed as to preclude any foreclosure of such rights by possible future application of the doctrine of res judicata arising from this determination.
Since, moreover, in the view of the District Court and apparently of the Court of Appeals, the Ohio class suit was dispositive of issues of unlawful discrimination arising out of the facts presented in that litigation without reference to § 8,18 it may be added that the Ohio determination could not apply, of course, to such discrimination taking place by virtue of later events.
We turn therefore to consideration of the sole question presented on the merits, namely, whether under § 8 the veteran’s right to statutory seniority extends indefinitely beyond the expiration of the first year of his reemployment, being unaffected by that event as long as the employment itself continues.
II.
The relevant portions of §§ 8 (a) and 8 (b) are set out in the margin.19 But we are concerned particularly with § 8 (c), which reads:
“Any person who is restored to a position in accordance with the provisions of paragraph (A) or (B) of subsection (b) shall be considered as naving been [52]*52on furlough or leave of absence during his period of training and service in the land or naval forces, shall be so restored without loss of seniority, shall be entitled to participate in insurance or other benefits offered by the employer pursuant to established rules and practices relating to employees on furlough or leave of absence in effect with the employer at the time such person was inducted into such forces, and shall not be discharged from such position without cause within one year after such restoration.”
The Government argues on respondent’s behalf that the correct meaning of § 8, and particularly of subsection (c), is that upon reemployment the veteran is entitled to retain indefinitely his prewar plus service-accumulated seniority.20 Under the statute, it says, this seniority can[53]*53not be taken away by a collective bargaining agreement or by the employer,21 either during the year in which the statute insures the veteran against discharge without cause or thereafter while the employment continues.22 Support for this view is thought to be derived from the syntax of the statutory language and from the legislative history.
It is argued that grammatically the “within one year” provision applies only to the last clause of subsection (c), relating to discharge without cause, and does not refer to the “other rights” 23 given by subsections (b) and (c), including restored statutory seniority. Because the “within one year” provision appears most proximately in connection with the prohibition against discharge, the Government seeks to give that prohibition, including its temporal term, effect as a command wholly distinct from [54]*54and unrelated to anything preceding. It treats the clause as a grammatically independent sentence and a substantively unrelated provision, although it is separated from the earlier ones only by a comma followed by the conjunction “and.”
On this premise of complete severability the Government builds its entire case. The premise necessarily regards § 8 (c) as making no express provision for the duration of “other rights,” but as leaving this to be found wholly by implication. The Government then goes on to conclude that the period to be implied is indefinite. Although the statutory security against discharge ends with the prescribed year, the protection given by § 8 (c) to “other rights” is said therefore not only to be effective for that year, cf. Fishgold v. Sullivan Dry dock & Repair Corp., supra, but to continue in full force for as long as the job may last beyond that time. In this view, of course, the result would be to “freeze” the incidents of the employment indefinitely while “freezing” the right to the job itself for only one year.
Difficulties arise in connection with this construction, both in its premise and in its conclusions. One is that the conclusion of indefinite duration would not follow necessarily, if the premise of complete severability were acceptable. On that basis “indefinite duration” as the Government conceives it would not be the only tenable period or even the most probably contemplated one. Several alternatives would be presented. However, the statutory year would not be among them, since it is implicit in the premise of severability that the Act does not apply the concluding clause of § 8 (c) to “other rights” to secure their extension either during or after that time. On the other hand, the Government’s view ignores the usual rule of construction where time is not expressly prescribed, but is evidently to be implied. For generally in such cases [55]*55duration for a reasonable period is the term accepted by the law rather than permanency or indefinite extension.24 And this, in varying circumstances, might be found to be longer or shorter than the statutory year prescribed for the job itself.
The real trouble however is in the basic premise both grammatically and substantively. It assumes not only the complete independence of the last clause of § 8 from what precedes, but also that employment within the meaning of the Act is something wholly distinct and separate from its incidents, including seniority, rates of pay, etc. We think, however, that the idea of total severability is altogether untenable. To accept it would do violence both to the grammatical and to the substantive structure of the statute.
The clause is neither an independent sentence nor a disconnected prohibition without significant relationship to what precedes. “From such position” has no meaning severed from the prior language. The restoration provisions define the very character of the place not only to which the veteran must be restored but equally from which he is not to be discharged. Neither grammatically nor substantively could the discharge provision be given effect without reference to the prior “restoration” clauses. Fishgold v. Sullivan Drydock & Repair Corp., supra. Indeed such reference is explicit both in the phrase “from such position” and in the time provision itself, namely, “within one year after such restoration.”
To tear the concluding clause from its context is therefore impossible. It is conjunctive with all that precedes. Nor is it any the more permissible to disconnect its constituent temporal term. There can be no doubt whatever that Congress intended by § 8 (c) to secure the “other [56]*56rights” guaranteed by it for at least the minimum term of the prescribed one-year period. This indeed was a specific ruling of the Fishgold case.
The employee there had not been discharged in the sense of being thrown out of his job altogether. He simply had been deprived of the opportunity to work by the operation of the seniority system when there was not sufficient work for both himself and other employees with greater seniority after he had been accorded his full standing under the Act. That standing included not only his seniority status as of the time he entered the armed forces, but also all that would have accumulated had he remained at work until the date of his reemployment without going into the service. In the language of § 8 (c) he is to be “considered as having been on furlough or leave of absence during his period of training and service in the land or naval forces.” The Court held, indeed, that the Act did not give him standing to outrank nonveteran employees who had more than the amount of seniority to which he was entitled and to which he had been restored; in other words, that he was not given so-called “superseniority.” But it also squarely held that he was given security not only against complete discharge, but also against demotion, for the statutory year. And demotion was held to mean impairment of “other rights,” including his restored statutory seniority for that year. “If within the statutory period he is demoted, his status, which the Act was designed to protect, has been affected and the old employment relationship has been changed. He would then lose his old position and acquire an inferior one. He would within the meaning of § 8 (c) be 'discharged from such position.’ ” 328 U. S. at 286.
That § 8 (c) applies to secure the protection of “other rights” for at least the statutory year was therefore inherent in the rationalization of the Fishgold decision. To that extent at any rate the concluding clause was held [57]*57applicable, not severable, concerning them. This of course destroys the Government’s basic premise of the complete severability of that clause and its resulting non-applicability to “other rights.” While the reemployed veteran did not acquire “superseniority,” § 8 (c) gave him the restored standing for the minimum duration of the prescribed year.
It is therefore clear that Congress did not confer the rights given as incidents of the restoration simply to leave the employer free to nullify them at will, once he had made it. Equally clearly Congress did not create them to be operative for the vaguely indefinite and variously applicable period of a reasonable time. But we cannot agree that they were given to last as long as the employment continues, unaffected by expiration of the one-year period.
To accept this conclusion, as we have said, would mean “freezing” the incidents of the employment indefinitely while “freezing” the right to employment itself for only one year. As long as the employee might remain in his job, his pay could not be reduced, his seniority could not be decreased, insurance and other benefits could not be adversely affected. And this would be true, although for valid reasons all of those rights could be changed to the disadvantage of nonveteran employees having equal or greater seniority and other rights than those of the veteran with restored statutory standing. The reemployed veteran thus not only would be restored to his job simply, as the Fishgold case required, “so that he does not lose ground by reason of his absence.” 328 U. S. at 285. He would gain advantages beyond the statutory year over such non-veteran employees.
We do not think Congress had in mind such far-reaching consequences for the nation-wide system of employment, both public and private, when making the statutory provisions for the veteran’s benefit. At the time it acted, [58]*58we had not declared war and the men who were called to service were being inducted for a year’s training, with the idea if not the assurance that they would return to civilian life and occupations at the end of that year, without prejudice because of their service. Visionary as this notion proved to be, it hardly can be taken to support the view that Congress contemplated “freezing” the specified incidents of restored employment indefinitely.
The Fishgold case, it is true, concerned only events taking place within the statutory year. As the Court of Appeals pointed out in distinguishing this case, 154 F. 2d at 871, the issues there involved no question of the reemployed veteran’s standing after the statutory year. But, as we have said, the decision did hold that § 8 (c) applies to “other rights” for the year. And the rationalization was wholly inconsistent with the idea that those restored rights continued indefinitely after the year, unaffected by its termination. The restored veteran, it was held, could not be disadvantaged by his service to the nation. He “was not to be penalized on his return by reason of his absence from his civilian job.” 328 U. S. at 284. He was to be restored and kept, for the year at least, in the same situation as if he had not gone to war but had remained continuously employed or had been “on furlough or leave of absence.” It is clear, of course, that this statutory addition to the veteran’s seniority status is not automatically deducted from it at the end of his first year of reemployment. But the Fishgold decision also ruled expressly that he was not to gain advantage beyond such restoration, by virtue of the Act’s provisions, so as to acquire “an increase in seniority over what he would have had if he had never entered the armed services. . . . No step-up or gain in priority can be fairly implied.” 328 U. S. at 285-286.
For the statutory year indeed this meant that the restored rights could not be altered adversely by the usual [59]*59processes of collective bargaining or of the employer’s administration of general business policy.25 But if this extraordinary statutory security were to be extended beyond the statutory year, the restored veteran would acquire not simply equality with nonveteran employees having identical status as of the time he returned to work. He would acquire indefinite statutory priority over non-veteran employees, a preferred status which we think not only inharmonious with the basic Fishgold rationalization, but beyond the protection contemplated by Congress.
We are unable therefore to accept the Government’s position. Aside from the events taking place after the Court of Appeals’ decision, which as we have said are not properly here for consideration except upon the question of mootness, Whirls was treated exactly as were other employees in his group having the same seniority and status as he had on the date of his reemployment. There was no discrimination against him as a veteran or otherwise than as a member of that group. Both groups, the former Trailmobile employees and the former Highland employees, who composed his group, contained veterans and nonveterans in large numbers. Both contained veterans in active service and reemployed veterans when the collective agreement was made. Whirls was treated exactly as all other members of his group, the ex-Highland employees, veterans and nonveterans alike. Whether or not the collective agreement was valid, or infringed rights [60]*60of Whirls and other members of that group apart from rights given by § 8 (c), is not before us, for reasons we have stated. The only question here and the only one we decide is that § 8 (c), although giving the reemployed veteran a special statutory standing in relation to “other rights,” as defined in the Fishgold case, during the statutory year, and creating to that extent a preference for him over nonveterans, did not extend that preference for a longer time.
On the facts therefore we are not required to determine the further question whether the statute would give protection to a reemployed veteran after the statutory year, if it were shown that he then had been demoted beneath his rightful standing under the Act as of the date of his restoration, though nonveteran employees having the same seniority standing as of that time had not been demoted or adversely affected. No such question is presented on the facts of record properly before us for consideration and decision. It will be time enough to consider such an issue whenever it may be presented.
We find it unnecessary therefore to pass upon petitioners’ position in this case, namely, that all protection afforded by virtue of § 8 (c) terminates with the ending of the specified year. We hold only that so much of it ends then as would give the reemployed veteran a preferred standing over employees not veterans having identical seniority rights as of the time of his restoration. We expressly reserve decision upon whether the statutory security extends beyond the one-year period to secure the reemployed veteran against impairment in any respect of equality with such a fellow worker.
These reasons, founded in the literal construction of the statute and the policy clearly evident on its face, are sufficient for disposition of the case. They are not weakened by the Government’s strained and unconvincing citation of the Act’s legislative history.
[61]*61That argument is grounded in conclusions drawn from changes made without explanation in committee with respect to various provisions finally taking form in § 8, changes affecting bills which eventually became the Selective Training and Service Act and the National Guard Act, 54 Stat. 858. Apart from the inconclusive character of the history, the Government’s contention assumes that the only alternatives presented by the final form of the bill were indefinite duration for the incidents of the employment named and none at all. This ignores the other possibilities considered in this opinion, including duration for a reasonable time. Moreover, as has been noted, the most important committee changes relied upon were made without explanation.26 The interpretation of statutes cannot safely be made to rest upon mute intermediate legislative maneuvers.27
The argument for respondent in this case is of whole cloth in principle with the contention for “superseniority” made and rejected in the Fishgold case, as indeed the District Court and the Court of Appeals regarded it. Lacking any better legislative footing, it equally cannot stand.
Accordingly the judgment of the Court of Appeals is reversed. This however will be without prejudice from the decision here to respondent’s assertion in the future of any rights he may have against Trailmobile or the col[62]*62lective agent on account of their acts not presented on this record or involved in the issues determined by this decision.
It is so ordered.