Article I, Section 2, Clause 2:
No Person shall be a Representative who shall not have attained to the Age of twenty five Years, and been seven Years a Citizen of the United States, and who shall not, when elected, be an Inhabitant of that State in which he shall be chosen.
Writing in The Federalist with reference to the election of Members of Congress, Hamilton firmly stated that
[t]he qualifications of the persons who may . . . be chosen . . . are defined and fixed in the constitution; and are unalterable by the legislature. 1 Until the Civil War, the issue was not raised, the only actions taken by either House conforming to the idea that the qualifications for membership could not be enlarged by statute or practice. 2 But in the passions aroused by the fratricidal conflict, Congress enacted a law requiring its members to take an oath that they had never been disloyal to the National Government. 3 Several persons were refused seats by both Houses because of charges of disloyalty, 4 and thereafter House practice, and Senate practice as well, was erratic. 5 But in Powell v. McCormack, 6 it was conclusively established that the qualifications listed in clause 2 are exclusive 7 and that Congress could not add to them by excluding Members-elect not meeting the additional qualifications. 8
Powell was excluded from the 90th Congress on grounds that he had asserted an unwarranted privilege and immunity from the process of a state court, that he had wrongfully diverted House funds for his own uses, and that he had made false reports on the expenditures of foreign currency. 9 The Court determination that he had been wrongfully excluded proceeded in the main from the Court's analysis of historical developments, the Convention debates, and textual considerations. This process led the Court to conclude that Congress’s power under Article I, § 5 to judge the qualifications of its Members was limited to ascertaining the presence or absence of the standing qualifications prescribed in Article I, § 2, cl. 2, and perhaps in other express provisions of the Constitution. 10 The conclusion followed because the English parliamentary practice and the colonial legislative practice at the time of the drafting of the Constitution, after some earlier deviations, had settled into a policy that exclusion was a power exercisable only when the Member-elect failed to meet a standing qualification, 11 because in the Constitutional Convention the Framers had defeated provisions allowing Congress by statute either to create property qualifications or to create additional qualifications without limitation, 12 and because both Hamilton and Madison in the Federalist Papers and Hamilton in the New York ratifying convention had strongly urged that the Constitution prescribed exclusive qualifications for Members of Congress. 13
Further, the Court observed that the early practice of Congress, with many of the Framers serving, was consistently limited to the view that exclusion could be exercised only with regard to a Member-elect failing to meet a qualification expressly prescribed in the Constitution. Not until the Civil War did contrary precedents appear, and later practice was mixed. 14 Finally, even were the intent of the Framers less clear, said the Court, it would still be compelled to interpret the power to exclude narrowly.
A fundamental principle of our representative democracy is, in Hamilton's words, ‘that the people should choose whom they please to govern them.’ 2 Elliot's Debates 257. As Madison pointed out at the Convention, this principle is undermined as much by limiting whom the people can select as by limiting the franchise itself. In apparent agreement with this basic philosophy, the Convention adopted his suggestion limiting the power to expel. To allow essentially that same power to be exercised under the guise of judging qualifications, would be to ignore Madison's warning, borne out in the Wilkes case and some of Congress’s own post-Civil War exclusion cases, against ‘vesting an improper and dangerous power in the Legislature.’ 2 Farrand 249. 15 Thus, the Court appears to say, to allow the House to exclude Powell on this basis of qualifications of its own choosing would impinge on the interests of his constituents in effective participation in the electoral process, an interest which could be protected by a narrow interpretation of Congressional power. 16
The result in Powell had been foreshadowed when the Court held that the exclusion of a Member-elect by a state legislature because of objections he had uttered to certain national policies constituted a violation of the First Amendment and was void. 17 In the course of that decision, the Court denied state legislators the power to look behind the willingness of any legislator to take the oath to support the Constitution of the United States, prescribed by Article VI, cl. 3, to test his sincerity in taking it. 18 The unanimous Court noted the views of Madison and Hamilton on the exclusivity of the qualifications set out in the Constitution and alluded to Madison's view that the unfettered discretion of the legislative branch to exclude members could be abused in behalf of political, religious or other orthodoxies. 19 The First Amendment holding and the holding with regard to testing the sincerity with which the oath of office is taken is no doubt as applicable to the United States Congress as to state legislatures.