delivered the opinion of the Court.

The question here is whether federal magistrates are authorized to conduct evidentiary hearings in federal habeas corpus cases. In 1968, Congress enacted the *463Federal Magistrates Act, 28 U. S. C. §§ 631-639, to upgrade and expand the former United States commissioner system. The Act authorizes magistrates to exercise all powers formerly exercised by United States commissioners,1 and also, as a means of relieving the caseload burden of the federal district judges, empowers magistrates to try minor offenses when all parties consent,2 and to perform such additional duties assigned by the district court as are “not inconsistent with the Constitution and laws of the United States.” 3 Pursuant to *464the Act, the Judges of the United States District Court for the Western District of Kentucky amended Local Rule 16 of that court to provide:

“In addition to submitting such other reports and recommendations as may be required concerning petitions for writs of habeas corpus from state prisoners the full-time Magistrate is directed to schedule and hear evidentiary matters deemed by the Magistrate to be necessary and proper in the determination of each such petition, and to report thereon with an appropriate recommendation for the disposition thereof to the District Judge having jurisdiction of the case. The Magistrate shall cause the testimony of such hearing to be recorded on suitable electronic sound recording equipment. He shall submit his proposed findings of fact and conclusions of law to the proper Judge for his consideration, copies of which shall be provided at that time to the petitioner and respondent, and the Magistrate shall expeditiously transmit the proceedings, including the recording of the testimony, to the proper District Judge. Upon written request of either party, filed within ten days from the date such is so transmitted to the District Judge having jurisdiction thereof, the District Judge shall proceed to hear the recording of the testimony given at the evidentiary hearing and give it de novo consideration.”

*465Respondent is a state prisoner whose petition for federal habeas corpus relief was assigned by the District Court to a full-time Magistrate for processing under the rule. The part of the rule challenged here is that which directs the full-time magistrate “to schedule and hear evidentiary matters [to be electronically recorded] deemed by the Magistrate to be necessary and proper in the determination of . . . such petition, and to report thereon with an appropriate recommendation for the disposition thereof to the District Judge [who] . . . [u]pon . . . request. . . shall proceed to hear the recording of the testimony . . . and give it de novo consideration.” The question is whether this portion of the rule is invalid because “inconsistent with the . . . laws of the United States” within the meaning of the Federal Magistrates Act, 28 U. S. C. § 636.(b), or because § 636 (b) itself should be construed to preclude district courts from assigning such duties to magistrates.

I

Respondent, Carl James Wedding, is a prisoner in the Kentucky State Penitentiary serving a life sentence imposed in 1949 by the Webster Circuit Court, Commonwealth of Kentucky, after a plea of guilty to a charge of willful murder. Wedding filed this petition for habeas corpus in 1971. After the Court of Appeals for the Sixth Circuit reversed the initial dismissal of his petition, 456 F. 2d 245 (1972), and remanded for an evidentiary hearing, the District Court invoked Local Rule 16 and assigned the case to a full-time Magistrate to hold the hearing. Wedding promptly moved that the Magistrate be disqualified and the hearing be reassigned to a District Judge, on the ground that the Federal Magistrates Act did not authorize district courts to assign to magistrates the duty to hold habeas corpus evidentiary hearings. When the District Court denied the motion, the Magistrate pro*466ceeded with the hearing, and electronically recorded all testimonial evidence as required by Local Rule 16. Thereafter, the Magistrate transmitted the recording of the testimony to the District Judge and submitted written findings of fact and conclusions of law recommending that the petition be dismissed.

Wedding moved that the District Court give the matter a de novo hearing. The District Judge's response was to listen, as authorized by Local Rule 16, to the recording of the hearing before the Magistrate. On this basis and the Magistrate's findings and conclusions, the District Court entered an order dismissing respondent’s petition.

On appeal, Wedding renewed his challenge to Local Rule 16, relying upon Holiday v. Johnston, 313 U. S. 342 (1941). Holiday was also a federal habeas corpus case. There, after determining that the petition for writ of habeas corpus alleged facts which, if proved, would entitle the petitioner to relief, the District Judge issued a writ compelling the respondent to produce the petitioner before a designated United States Commissioner. The Commissioner held an evidentiary hearing at which the petitioner testified and the respondent submitted the depositions of two witnesses. On the basis of the evidence received, the Commissioner made findings of fact and stated conclusions of law recommending that the writ be denied. After hearing oral argument on the Commissioner's report, the District Judge entered an order discharging the writ.

This Court reversed, holding that the factfinding procedure employed failed to conform to Congress' express command in the Habeas Corpus Act that “[t]he court, or justice, or judge shall proceed in a summary way to determine the facts of the case, by hearing the testimony and arguments, and thereupon to dispose of the party as law and justice require.” Rev. Stat. § 761, *46728 U. S. C. §461 (1940 ed.) (emphasis added). The Court held that the statute plainly accords a prisoner the right of testifying before a judge, stating:

“One of the essential elements of the determination of the crucial facts is the weighing and appraising of the testimony. Plainly it was intended that the prisoner might invoke the exercise of this appraisal by the judge himself. We cannot say that an appraisal of the truth of the prisoner’s oral testimony by a master or commissioner is, in the light of the purpose and object of the proceeding, the equivalent of the judge’s own exercise of the function of the trier of the facts.

“The District Judge should himself have heard the prisoner’s testimony and, in the light of it and the other testimony, himself have found the facts and based his disposition of the cause upon his findings.” Holiday v. Johnston, supra, at 352, 353-354.

Wedding contended that neither the text nor legislative history of the Federal Magistrates Act evidences a congressional intent to overrule Holiday. The Court of Appeals agreed and accordingly “vacate[d] the judgment of dismissal and remand [ed] the case with instructions that the [District] Court itself hold an evidentiary hearing on [Wedding’s] constitutional claims.” 483 F. 2d 1131, 1137 (CA6 1973). We granted certiorari, 414 U. S. 1157 (1974). We affirm.4

*468II

Under our constitutional framework, the “great constitutional privilege” of habeas corpus, Ex parte Bollman 4 Cranch 75, 95 (1807) (Marshall, C. J.), has historically provided “a prompt and efficacious remedy for whatever society deems to be intolerable restraints. Its root principle is that in a civilized society, government must always be accountable to the judiciary for a man’s imprisonment: if the imprisonment cannot be shown to conform with the fundamental requirements of law, the individual is entitled to his immediate release.” Fay v. Noia,, 372 U. S. 391, 401-402 (1963). More often than not, claims of unconstitutional detention turn upon the resolution of contested issues of fact. Accordingly, since the Judiciary Act of February 5, 1867, c. 28, § 1, 14 Stat. 385, Congress has expressly vested plenary power in the federal courts “for taking testimony and trying the facts anew in habeas hearings . ...” 5 Fay v. Noia, supra, at 416. See also Townsend v. Sain, 372 U. S. 293, 312 (1963).

In connection with the 1948 revision and recodification of the Judicial Code,6 Rev. Stat. § 761, construed in Holiday, and other procedural provisions of the Habeas Corpus Act were consolidated into 28 U. S. C. § 2243. The pertinent portion covering habeas corpus evidentiary hearings provides that “[t]he court shall summarily hear and determine the facts, and dispose of the matter as law and justice require.” The Revisers thus deleted some *469words from Rev. Stat. § 761, but the Revisers’ Notes accompanying § 2243, together with the reports of the Committee of the Judiciary of the Senate,7 and of the House,8 make abundantly clear that the word changes and omissions in Rev. Stat. § 761 were intended only as changes in form.9

Accordingly, the construction of § 2243 has been that given § 761 in Holiday. United States v. Hayman, 342 U. S. 205, 213 n. 16 (1952); Brown v. Allen, 344 U. S. 443, 462-463 (1953). The Court held in the latter case:

“A federal judge on a habeas corpus application is required to ‘summarily hear and determine the facts, and dispose of the matter as law and justice require,’ 28 U. S. C. § 2243. This has long been the law. R. S. § 761, old 28 U. S. C. § 461.” Ibid, (emphasis added).

Ill

Our inquiry is thus narrowed to the question whether the Federal Magistrates Act changed the requirement of § 2243 that federal judges personally conduct habeas corpus evidentiary hearings. Certainly nothing in the text *470or legislative history of the Magistrates Act suggests that Congress meant to change that requirement.10 Rather, both text and legislative history plainly reveal a congressional determination to retain the requirement. For, although the Act gives district judges broad authority to assign a wide range of duties to magistrates, Congress carefully circumscribed the permissible scope of assignment to only “such additional duties as are not inconsistent with the Constitution and laws of the United States.” 28 U. S. C. § 636 (b) (emphasis added). And in defining assignable duties, Congress decreed that the duty of holding evidentiary hearings was not assignable. This clearly emerges from the legislative history of subsection (3) of § 636 (b), which provides:

“(3) preliminary review of applications for post-trial relief made by individuals convicted of criminal offenses, and submission of a report and recommendations to facilitate the decision of the district judge having jurisdiction over the case as to whether there should be a hearing.” (Emphasis added.)

That legislative history reveals that the Judicial Conference of the United States objected to successive phrasings of subsection (b) (3) until it was phrased to make clear that the authority given district courts to assign duties to magistrates did not include authority to hold evi-dentiary hearings on applications for posttrial relief.11 *471The original draft of the subsection12 had proposed that magistrates’ duties include

“(3) preliminary consideration of applications for post-trial relief made by individuals convicted of criminal offenses.”

But because that language was susceptible of the interpretation that magistrates might conduct evidentiary hearings, the Judicial Conference of the United States objected to it.13 Accordingly, the subsection was rewritten to provide for

“(3) preliminary review of applications for post-trial relief made by individuals convicted of criminal offenses, and submission of a report and recommendations to facilitate the decision of the district judge having jurisdiction over the case ...

The Committee on the Administration of the Criminal Law of the Judicial Conference objected that the revision did not “make it clear that it is the judge’s responsibility to make the ultimate decisions and to hold hearings on such applications, rather than that of the *472magistrate.” 14 The Committee therefore recommended the addition of the phrase “as to whether there should be a hearing” immediately following the word “case.”15 The proposed addition was made,16 and subsection (b) (3) in its present form was enacted. Thus, although § 636 (b) provides that “additional duties authorized by rule may include, but are not restricted to,” duties defined in subsection (b) (3), the legislative history of the subsection compels the conclusion that Congress made a deliberate choice to preclude district courts from assigning magistrates the duty to hold evidentiary hearings.

We conclude that, since § 2243 requires that the District Judge personally hold evidentiary hearings in federal habeas corpus cases, Local Rule 16, insofar as it authorizes the full-time magistrate to hold such hearings, is invalid because it is “inconsistent with the . . . laws of the United States” under §636 (b). We conclude further that the Rule is to that extent invalid because, as we construe § 636 (b), that section itself precludes district judges from assigning magistrates the duty of conducting evidentiary hearings.17 Review by magistrates of applications for post-trial relief is thus limited to review for the purpose of proposing, not holding, eviden-*473tiary hearings.18 In connection with the preliminary review whether or not to propose that the district judge hold an evidentiary hearing, we agree that magistrates may receive the state court record and all affidavits, stipulations, and other documents submitted by the parties.19 Magistrates are prohibited only from conducting the actual evidentiary hearings.20

The invalidity of Local Rule 16 is not cured by its provision that the “District Judge shall proceed to hear *474the recording of the testimony given at the evidentiary hearing and give it de novo consideration.” Holiday reasoned that the command of § 761, now § 2243, was designed by Congress in recognition that “[o]ne of the essential elements of the determination of the crucial facts is the weighing and appraising of the testimony.” 313 U. S., at 352. “To experienced lawyers it is commonplace that the outcome of a lawsuit — and hence the vindication of legal rights — depends more often on how the factfinder appraises the facts than on a disputed construction of a statute or interpretation of a line of precedents. Thus the procedures by which the facts of the case are determined assume an importance fully as great as the validity of the substantive rule of law to be applied.” Speiser v. Randall, 357 U. S. 513, 520 (1958). Congress, Holiday held, “[p]lainly . . . intended that the prisoner might invoke . . . appraisal by the judge himself.” In that circumstance, we “cannot say that an appraisal of the truth of the prisoner’s oral testimony” based on listening to a recording of it, “is, in the light of the purpose and object of the proceeding, the equivalent of the judge’s own exercise of the function of the trier of the facts.” 313 U. S., at 352.

Affirmed.

dissenting.

The Court today reads two separate statutes and our prior cases to reach a result contrary to the purposes underlying the enactment in 1968 of the Federal Magistrates Act, 28 U. S. C. § 631 et seq., and to the conclusion of every other Court of Appeals which has had occasion to consider the matter.1

*475The Federal Magistrates Act was both “designed to create an upgraded lower tier judicial office/' S. Rep. No. 371, 90th Cong., 1st Sess., 11 (1967), and “intended ... to cull from the ever-growing workload of the U. S. district courts matters that are more desirably performed by a lower tier of judicial officers.” H. R. Rep. No. 1629, 90th Cong., 2d Sess., 12 (1968). The Court’s holding that federal magistrates may not conduct evidentiary hearings in federal habeas corpus cases is both inconsistent with the new status of magistrates and deputy magistrates,2 and serves to defeat the objective of the Act, *476described by Senator Tydings, its principal sponsor, see n. 2, supra, “to provide district judges with more time to devote to the actual trial of cases and the writing of opinions.” 3 Hearings 3.

I

In its two-stage analysis, the Court finds first that under the terms of the Act it would be “inconsistent with *477the . . . laws of the United States,” 28 U. S. C. § 636 (b), to permit magistrates to conduct evidentiary hearings in habeas corpus cases. This is so, it is said, because a procedural provision of the Habeas Corpus Act, Rev. Stat. § 761, was construed 33 years ago, long before the enactment of the Magistrates Act, to confine that function to judges alone. Holiday v. Johnston, 313 U. S. 342 (1941). The 1948 revision and recodification of the Judicial Code, which incorporated Rev. Stat. § 761 into 28 U. S. C. § 2243, is held to have carried forward this limitation despite a critical language change. United States v. Hayman, 342 U. S. 205 (1952); Brown v. Allen, 344 U. S. 443 (1953). Neither the new statute, its drafting history, nor these latter cases, support the Court’s conclusion.

Section 2243 did, as the Court notes, import into its terms Rev. Stat. § 761, both of which provisions set forth in part what authority shall hear and determine the facts involved in an application for a writ of habeas corpus. And § 2243 changed the language of Rev. Stat. § 761, which originally read that the authority was to be the “court, or justice, or judge,” now to read simply the “court.” But the Court fails to note that § 2243 incorporated a second provision from the Habeas Corpus Act, Rev. Stat. § 755, which in part set forth what authority shall issue the writ of habeas corpus for which application was made. The authority to issue the writ set forth in Rev. Stat. § 755 was identical to that set forth in Rev. Stat. §761 to hear and determine the facts: the “court, or justice, or judge.” Unlike the language of Rev. Stat. § 761, however, the quoted language of Rev. Stat. § 755 was incorporated into § 2243 substantially unchanged; under the present statute, it is the “court, justice or judge” who shall issue the writ.

Congress sought to make certain that only a “court, justice or judge” could issue the writ; but by changing *478the authority to hear the facts from a “court, or justice, or judge” to, simply, a “court,” Congress must have intended to broaden the authority of the court, at least to the extent of permitting delegation to a magistrate to perform the preliminary hearing function, subject always to the approval of a district judge.4 To read the language change in any other way would impute to Congress an intent to alter statutory language, the meaning of which had already been finally determined by this Court, Holiday v. Johnston, supra, without the knowledge that the alteration would raise interpretive difficulties. Moreover, to change the language of Rev. Stat. § 761, but not to change that of Rev. Stat. § 755, cannot be said, as the Court does, ante, at 469 n. 9, to be a “[m]ere change of phraseology,” for such changes were undertaken only for purposes of uniformity. If, as Charles J. Zinn, counsel to the Law Revision Committee which revised the Judicial Code, testified, “we have changed the language to get a uniform style,” 5 then within the same statutory provision, surely Congress would have made only “courts” able to issue writs, as well as hear the facts of the claim.

Nor do the cases cited by the Court, ante, at 469, support its interpretation of § 2243. Brown v. Allen, supra, is plainly inapposite. The segment of Brown quoted by the Court is relevant to Brown’s discussion of whether a petitioner under 28 U. S. C. § 2254 had a right to a plenary hearing although an earlier petition of his which presented substantially the same federal issues was refused in the state court. When the Court quotes from Brown: *479“This has long been the law,” ante, at 469, it is referring to what the Brown Court called the “general rule” approved in Salinger v. Loisel, 265 U. S. 224, 231 (1924). Brown, 344 TJ. S., at 463. Salinger in turn makes it clear that the “general rule” which has “long been the law” has nothing whatever to do with who may hear and determine the facts on an application for a writ of habeas corpus. Rather, it pertains only to that portion of § 2243 which Brown itself quoted, 344 U. S., at 462, and which Salinger also quoted, 265 U. S., at 231, that is, “to dispose of [the matter or party] as law and justice [may] require.” In Salinger, this rule meant each application for a writ of habeas corpus could be disposed of in the exercise of judicial discretion, which could in part give controlling weight to “a prior refusal [by a federal court] to discharge on a like application.” Ibid. In Brown, that rule was extended under certain circumstances to a prior state court refusal to issue the writ, in support of the Court’s conclusion there that a § 2254 petitioner had no right to a plenary hearing on his application for the writ. The rule the Court relies on today is thus one of discretion to hold an evidentiary hearing “as law and justice require,” which has no bearing on what official shall conduct the hearing once a decision is made to hold one. Brown is thus no authority for the proposition that the same limitation Holiday placed on Rev. Stat. § 761 (“court, or justice, or judge”) applies to § 2243 (“court”) enacted after Holiday.

The Court also relies upon United States v. Hayman, supra, to support its interpretation of § 2243. The issue in Hayman had nothing to do with who shall hear and determine facts upon an application for a writ of habeas corpus. Rather, the Court there was concerned solely with the question whether a district court may, upon an evidentiary hearing, decide factual issues pre*480sented by a motion under 28 U. S. C. § 2255, where the movant was not notified and was not present. In the context of discussing an earlier case which had held that a district court must decide material issues of fact by taking evidence, not by ex parte affidavits, Hay man dropped a footnote stating simply “[n]or can the factual issues be heard before a commissioner,” citing Holiday, supra. 342 U. S., at 213 n. 16. Not only was this footnote completely irrelevant to the issue in Hay man, its citation to Holiday for support, without further discussion, makes manifest that the Court did not consider the effect of the subsequent language change in § 2243 on the statute (Rev. Stat. § 761) which Holiday construed. The fulfillment of the purposes of the Federal Magistrates Act should not hang on such a slim reed.

II

Even assuming that § 2243 was intended to carry forward the limitation of Holiday’s interpretation of its predecessor, by enacting the Magistrates Act, and particularly § 636 (b) thereof, Congress made clear its intent to eliminate that restriction. Thus, while Hayman may speak in terms of a “commissioner,” Congress changed not only the title of that office, but also the qualifications for and the functions of the office.

Section 636 (b) permits federal magistrates to “be assigned . . . such additional duties as are not inconsistent with the Constitution and laws of the United States.” The section then sets forth in three subdivisions certain duties which district courts may authorize by rule, but the duties “are not restricted to” those set forth. The third illustrative subdivision provides that district courts may authorize the additional duty of

“preliminary review of applications for posttrial relief made by individuals convicted of criminal of*481fenses, and submission of a report and recommendations to facilitate the decision of the district judge having jurisdiction over the case as to whether there should be a hearing.” 28 U. S. C. § 636 (b) (3).

Subdivision (3), suggesting additional duties that maybe assigned to a magistrate in connection with federal habeas corpus cases, does not by its terms permit magistrates to conduct evidentiary hearings, but that subdivision is merely illustrative, not exclusive.

“The mention of these three categories is intended to illustrate the general character of duties assignable to magistrates under the act, rather than to constitute an exclusive specification of duties so assignable.” S. Rep. No. 371, 90th Cong., 1st Sess., 25 (1967).

The House Report virtually tracks the language of the Senate Report. H. R. Rep. No. 1629, 90th Cong., 2d Sess., 19 (1968). Thus, there being no constitutional barrier to permitting magistrates to conduct evidentiary hearings,6 nor any other legal barrier, see Part I, supra, § 636 (b) enables district courts, as did the District Court here, to establish rules which so permit.

Assuming, arguendo, that § 2243 does constitute a possible legal barrier to such rules, the legislative history of the Act reveals Congress to have intended the elimination of that barrier. The Court determines, in the second stage of its analysis, ante, at 469-473, that Congress intended the opposite result, but in this matter the Court’s perception is less than discriminating. The linchpin of the Court’s argument is the drafting evolution of the terms of subdivision (3), quoted above. In the change of language from preliminary “consideration” to preliminary *482“review,” 7 and in the addition of “as to whether there should be a hearing,” 8 the Court finds an intent to bar magistrates from conducting a hearing. But the language changes in the subdivision were made only due to a fear that magistrates would be thought to have been given final adjudicatory power, not to preclude them from conducting hearings when the district judges retained such power.9 Indeed, the latter was specifically intended. As the Senate Report stated, § 636 (b)

“contemplates assignments to magistrates under cir*483cumstances where the ultimate decision of the case is reserved to the judge . ..S. Rep. No. 371, 90th Cong., 1st Sess., 26 (1967).

The concern about enabling magistrates to make the ultimate decision found early expression in the Senate hearings on the bill in a colloquy between Senator Tydings and then Assistant Attorney General Vinson. Mr. Vinson ultimately revealed his real concern in a letter to the Subcommittee that subdivision (3) as originally drafted would give the power of ultimate decision to the magistrate: “[I]f preliminary consideration is intended to involve adjudication, it should be handled by an Article 3 Judge.” Hearings 130. That the Senate viewed Mr. Vinson’s objections in this light is made clear by Senator Tydings’ testimony in the hearings before a subcommittee of the House Judiciary Committee. Hearings on S. 945 et al. before Subcommittee No. 4 of the House Committee on the Judiciary, 90th Cong., 2d Sess., 72 (1968).

In response to this objection, Senator Tydings stated to Mr. Vinson at the Senate hearings:

“We wouldn’t intend for the final decision to be made by the magistrate. But we would intend that . . . the magistrate [be able to] hold a preliminary [habeas] hearing .... We certainly intend that.” Hearings 112. (Emphasis added.)

Numerous other witnesses at the Senate hearings urged that the magistrates be permitted to hold hearings. See, *484e. g., id., at 52 (Chief Judge Northrop, supra, n. 3); id., at 94 (Chief Judge Walter E. Hoffman, of the Eastern District of Virginia).

As the Court points out, ante, at 470-471, the Judicial Conference objected to the original draft bill (S. 3475), but it did not originally object to subdivision (3), as the Court states. Instead, the Conference objected to § 636 (b) altogether, fearing it so broad as to be subject to constitutional attack. Although not specified, it seems clear that by speaking in terms of “delegation” the Conference initially shared Mr. Vinson’s concern about delegating the ultimate decisionmaking power of Art. Ill judges. Hearings 241n. The Judicial Conference therefore recommended both a modified version of § 636 (b), and the complete elimination of all three subdivisions. Ibid. When the revised draft bill (S. 945), which ultimately was enacted, was introduced, it did not follow the Judicial Conference recommendation, but continued to include the three subdivisions. As to subdivision (3), the Judicial Conference recommended the addition of the phrase “as to whether there should be a hearing,” see n. 7, supra, but again stressed that its concern was, as with S. 3475, over the “delegation to magistrates.” Hearings 245.

The tension established in this evolution is clear. On the one hand, Congress sought to enable district courts to authorize magistrates to conduct evidentiary hearings. On the other hand, there was apprehension that the power of authorization granted to district courts might lead to a rule permitting magistrates to exercise ultimate deci-sionmaking power reserved exclusively to Art. Ill judges. To avoid the latter but accomplish the former, Congress persisted in retaining the broad language of § 636 (b), and in retaining subdivision (3). Not only, as set *485forth earlier, does the subdivision not limit the subsection, it was drafted in language to insure that it could not be read to preclude authorizing magistrates to conduct hearings in federal habeas corpus cases.10

Plainly, Congress could have used language that expressly precluded the latter. That this was not urged upon Congress by anyone, including the Judicial Conference, and that Congress did not include such language, alone suggests its intention to vest in district courts the power to authorize magistrates to hold hearings. Conversely, Congress would have taken certain risks had it expressly permitted magistrates to hold hearings, as revealed by the following colloquy between Chief Judge Hoffman and Senator Tydings at the Senate hearings:

"Judge Hoffman. ... And I have suggested in my statement . . . that the Federal magistrate could be assigned the task as a master to conduct plenary hearings. After all, [habeas corpus proceedings] are civil proceedings . . . not criminal proceedings.

“Senator Tydings. [Sjince we . . . don’t have [in § 636 (b)] ‘Including hearings’ or ‘Including plenary hearings,’ or ‘including the conducting of plenary hearings,’ it is not what we should have?

“Judge Hoffman. I am fearful that someone will say that this is merely an effort on the part of the judge to delegate his judicial function.

“Senator Tydings. I think that is a good point, Judge Hoffman.” Hearings 93-94.

In light of the need for Congress to avoid language suggesting an unconstitutional delegation of a judicial *486function to a magistrate, the ambiguous provision of § 636 (b) — unlimited by the provisions of subdivision (3) — should be interpreted to permit magistrates to conduct evidentiary hearings in federal habeas corpus cases, § 2243 notwithstanding, because (1) to the extent the subject was expressly discussed in the legislative history, such permission was intended, and (2) such an interpretation would serve the two principal objectives of the Act. See nn. 2 and 3, supra.

Ill

The final limitation of the Act, that additional duties assigned to magistrates must not be “inconsistent with the Constitution,” needs little discussion here. The Court does not suggest that the conduct of an evidentiary hearing, where the district judge retains the power to make the final decision on an application for a writ of habeas corpus, would be unconstitutional either under Art. Ill or as a matter of due process of law. Where this situation obtains, the magistrate’s conduct of the hearing would be clearly constitutional.11

*487Not only would his report and recommendation to the district judge be subject to amendment or outright rejection, the district judge could, at the behest of the habeas corpus petitioner or on his own motion, conduct his own evidentiary hearing to judge for himself, for example, the credibility of witnesses if he deems their testimony essential to disposition of the application. To the extent a problem of constitutional magnitude may be foreseen in the particulars of the rules established by a district court, those rules can be construed to comport with constitutional requirements. In any event, now that the Court has construed the Magistrates Act contrary to a clear legislative intent, it is for the Congress to act to restate its intentions if its declared objectives are to be carried out.