with whom Mr. Justice Brennan concurs, dissenting in part.
While I agree with the Court that the cases are not moot and that the three-judge court was not barred by 28 U. S. C. § 2283 from issuing an injunction, I disagree on the merits.
*27By virtue of Art. I, § 5, Senate custom, and this Court’s prior holdings, the Senate has exclusive authority to settle a recount contest once the contestee has been certified and seated, albeit conditionally.
Article T, § 5, provides: “Each House shall be the Judge of the Elections, Returns and Qualifications of its own Members.” To implement this authority, the Senate has established a custom of resolving disagreements over which of two or more candidates in a senatorial race attracted more ballots. The apparent loser may initiate the process by filing with the Senate a petition stating (a) what voting irregularities he suspects, and (b) how many votes were affected. Upon receipt of such a petition, a special committee may be authorized to investigate the charges alleged. If the allegations are not frivolous and would be sufficient, if true, to alter the apparent outcome of the election, actual ballots may be and have been subpoenaed to Washington for recounting by the committee. Also, witnesses may be required to testify. The committee performs the function of deciding both the factual issues and what allegations would be sufficient to warrant favorable action on a petition.
Thus, in the Iowa senatorial campaign of 1924, Smith Brookhart was the apparent winner over Daniel Steck, who filed with the Senate the complaint that illegal votes had been cast for his opponent. The petition was referred to the Subcommittee on Privileges and Elections which was authorized to make a full investigation. It heard testimony and recounted the ballots in Washington. The committee and eventually the Senate agreed that, contrary to earlier assumptions, Steck had won. Accordingly, Brookhart was replaced by Steck as a Senator from Iowa. See Steck v. Brookhart, Senate Election, Expulsion and Censure Cases from 1789 to 1960, S. Doc. No. 71, 87th Cong., 2d Sess., 116-117 (1962). See also Hurley v. Chavez, id., at 151 (upon re*28counting, the subcommittee and the Senate found that neither candidate had won and the seat was declared vacant); Sweeney v. Kilgore, id., at 145 (adjustments for fraudulent campaign tactics were insufficient to reverse official outcome); O’Conor v. Markey, id., at 144 (recount of all votes cast in 1946 Maryland race revealed too few mistakes to cause reversal in outcome); Willis v. Van Nuys, id., at 138-139 (petition rejected as insufficient grounds for recount); Bursum v. Bratton, id., at 114 (recount will not be conducted absent a showing of grounds to doubt the accuracy of official count).
The Senate’s procedure is flexible:
“The Senate has never perfected specific rules for challenging the right of a claimant to serve, inasmuch as each case presents different facts. The practice has been to consider and act upon each case on its own merits, although some general principles have been evolved from the precedents established.
“This practice of viewing each case affecting claims to membership on its individual merits has resulted in a variety of means by which the cases are originated. The Senator-elect to a seat in the Senate generally appears with his credentials. On some occasions, when these credentials are presented, some Senators will submit a motion that the credentials be referred to the Committee on Rules and Administration, and that, pending report, he be denied the privilege of taking the oath of office. Upon adoption of such a motion, the Senator-elect steps aside and the Senate seat is vacant for the time being. Any question or motion arising or made upon the presentation of such credentials is privileged and would be governed by a majority vote.
“On other occasions, the Senator-elect is permitted to take the oath of office, and this is now regarded and *29followed as the proper procedure, but thereafter inquiry as to his election is undertaken by the Senate. Resolutions calling for such investigations may be offered by any Senator. In an instance where a newspaper charged a Senator had obtained his office by illegal means, the Senator himself offered a resolution calling for an investigation of the charges.
“The usual origin of such cases, however, is by petition. The contestant may file such a petition, protesting the seating of the contestee, and asserting his own right to the seat in question. It is not required to be filed prior to the swearing-in of the contestee, and no rights are lost if filed afterwards. In some cases, petitions have been signed and filed by others than the contestant, simply protesting against the seating of the contestee, without asserting any claim in behalf of the defeated candidate. Any number of citizens may submit such a petition; and it might make charges of illegal practices in the election, or of the improper use of money, or even of the unfitness of the claimant to serve in the United States Senate.
“A petition of contest is addressed to the U. S. Senate, and may be laid before the Senate by the presiding officer or formally presented by some Senator. There is no prescribed form for such a petition. It is somewhat analogous to a complaint filed in a lawsuit. It customarily sets forth the grounds or charges upon which the contest is based, and in support of which proof is expected to be adduced. The petition is usually referred to the Committee on Rules and Administration, which has jurisdiction over '. . . matters relating to the election of the President, Vice President, or Members of Congress; corrupt practices; contested elections; credentials arid qualifications; [and] Federal elections generally . . . .’
*30“The Legislative Reorganization Act of 1946 empowers each standing committee of the Senate, including any subcommittee of any such committee, to hold such hearings, to sit and act at such times and places during the sessions, recesses, and adjourned periods of the Senate, to require by subpena or otherwise the attendance of such witnesses and the production of such correspondence, books, papers, and documents, to take such testimony and to make such expenditures (not in excess of $10,000 for each committee during any Congress) as it deems advisable. Each such committee may make investigations into any matter within its jurisdiction and may report such hearings as may be had by it.” S. Doc. No. 71, 87th Cong., 2d Sess., vii-viii (1962).
The parties before the Court are apparently in agreement that, as is true of several other arenas of public decisionmaking, there has been a “textually demonstrable constitutional commitment” (Baker v. Carr, 369 U. S. 186, 217; Powell v. McCormack, 395 U. S. 486, 518-549) to the Senate of the decision whether Hartke or Roudebush received more lawful votes. Our case law agrees. Both Barry v. Cunningham, 279 U. S. 597, and Reed v. County Comm’rs, 277 U. S. 376, were generated during the disputed 1926 senatorial election in Pennsylvania in which William Vare appeared to have defeated William Wilson. In 1926 a Senate committee was authorized to inquire into the means used to influence the nomination of candidates in that election. The committee asked some local county commissioners to produce certain ballots but were refused, whereupon members of the committee sought a federal court order compelling the ballots’ production. On appeal, this Court held that because the Senate had been fully competent to use its own subpoena power to secure the ballots, the District Court had lacked jurisdiction to act only at *31the behest of the committee. In the course of discussing the committee’s scope of authority the Court said:
“The resolutions are to be construed having regard to the power possessed and customarily exerted by the Senate. It is the judge of the elections, returns and qualifications of its members. Art. I, § 5. It is fully empowered, and may determine such matters without the aid of the House of Representatives or the Executive or Judicial Department. That power carries with it authority to take such steps as may be appropriate and necessary to secure information upon which to decide concerning elections.” 277 U. S., at 388.
In Barry v. Cunningham, supra, the Court upheld the Senate’s power under Art. I, § 5, to call witnesses before it in order to determine the factual history of the same controverted 1926 election involved in Reed. In answer to the argument that Vare had not been a member of the Senate inasmuch as he was unseated (and therefore the witness was relieved of the duty to answer inquiries) the Court held:
“It is enough to say . . . that upon the face of the returns [Vare] had been elected and had received a certificate from the Governor of the state to that effect. Upon these returns and with this certificate, he presented himself to the Senate, claiming all the rights of membership. Thereby, the jurisdiction of the Senate to determine the rightfulness of the claim was invoked and its power to adjudicate such right immediately attached by virtue of § 5 of Article I of the Constitution.” Barry v. Cunningham, supra, at 614.
And Cunningham holds that, “The Senate, having sole authority under the Constitution to judge of the elections, returns and qualifications of its members, may exer*32cise in its own right the incidental power of compelling the attendance of witnesses without the aid of a statute.” Id., at 619 (emphasis added). Judicial interference with this “indubitable power” was said to be possible only upon a clear showing of “such arbitrary and improvident use of the power as will constitute a denial of due process of law.” Id., at 620.
Once certification by the Governor has been presented to the Senate, a State may not by conducting a recount alter the outcome of the election — a principle that has been widely recognized by state courts. See Laxalt v. Cannon, 80 Nev. 588, 397 P. 2d 466, and cases cited therein.
Thus, although the Houses of Congress may not engraft qualifications for membership beyond those already contained in Art. I, Powell v. McCormack, 395 U. S. 486, where all that is at stake is a determination of which candidates attracted the greater number of lawful ballots, each has supreme authority to resolve such controversies.1
Although all agree that in the end the Senate will be the final judge of this seating contest, the nub of the instant case comes down to opposing positions on how important it may be to preserve for the Senate the opportunity to ground its choice in unimpeachable evidence. It is with regard to this phase of the cases that I disagree with the majority.
The Senate may conclude that only a recomputation supervised by it under laboratory conditions could serve as an acceptable guide for decision. Such a recomputation, however, will not be possible once local investigators have exposed these presently sealed ballots to human judgment.
*33Obviously, state officials might desire to preview these presently sealed ballots in order to influence the Senate’s deliberations.
Charges or suspicions of inadvertent or intentional alteration, however baseless, will infect the case. No longer will the constitutionally designated tribunal be able to bottom its result on unassailed evidence. Since even a slight adjustment in the tally could dramatically reverse the outcome, the federal interest in preserving the integrity of the evidence is manifest.
What the Senate should do in the merits is not a justiciable controversy. The role of the courts is to protect the Senate’s exclusive jurisdiction over the subject matter, as did this Court in Barry v. Cunningham, supra. The Senate’s Subcommittee on Privileges and Elections, for example, might subpoena these ballots, thereby precluding, as a practical matter, any local recount. Or the Senate might ask for a local recount. Either course is within the control and discretion of the Senate and is unreviewable by the courts. The District Court had jurisdiction only to protect the Senate’s choice,2 not to make the choice for or on behalf of the Senate.
I would affirm the judgment of the District Court.
Several areas of decisionmaking are immune from judicial review by federal courts. The cases are reviewed in Baker v. Carr, 369 U. S. 186.
Cf. Ex parte Peru, 318 U. S. 578.