There are three, and only three, standing qualifications for U.S. Senator or Representative in Congress which are expressly set out in the U.S. Constitution: age (25 for the House, 30 for the Senate); citizenship (at least seven years for the House, nine years for the Senate); and inhabitancy in the state at the time elected. U.S. Constitution, Article I, Section 2, cl. 2 (House); and Article I, Section 3, cl. 3 (Senate). The Supreme Court of the United States has affirmed the historical understanding that the Constitution provides the exclusive qualifications to be a Member of Congress, and that neither a state nor Congress itself may add to or change such qualifications to federal office, absent a constitutional amendment. Powell v. McCormack, 395 U.S. 486, 522 (1969); U.S. Term Limits, Inc. v. Thornton, 514 U.S. 779, 800-801 (1995); Cook v. Gralike, 531 U.S. 510 (2001). The Constitution expressly delegates to each house of Congress the authority to be the final judge of the qualifications of its own Members (Article I, Section 5, cl. 1). In judging the qualifications of their Members, and deciding by majority vote, the House and Senate are limited to judging only the qualifications set out in the Constitution. Powell v. McCormack, supra. Although the states have no authority to add to the constitutional qualifications for congressional office, the states have the responsibility under the "Times, Places, and Manner" clause of the U.S. Constitution (Article I, Section 4, cl. 1) for administering elections for federal office, including regulating such subjects as ballot design, candidate placement on the ballot, ballot security measures, nomination procedures to appear as a party's nominee on the ballot, and ballot access requirements for independent and new or minor political party candidates. Legitimate "ballot access" rules and regulations, even though they may pose certain administrative requirements on federal candidates, have been upheld when they have been found to be within a state's constitutional authority to regulate the election process, to ensure orderly elections, and to prevent fraud and voter confusion. The states have been allowed to implement rules which, for example, prevent over-crowding and confusion on the ballot by requiring a minimum show of public support to appear on the ballot, by prohibiting such things as dual candidacies on the ballot, and by implementing "sore loser" laws that bar a candidate on the general election ballot from appearing as an independent if that candidate had lost a party primary. Such administrative requirements have not been deemed to be additional "qualifications" to run for office. However, requirements that are more than merely administrative and procedural or measures to protect ballot integrity have been found to be unconstitutional as additional qualifications for office. Examples include requirements for congressional candidates to live in the congressional district (and not just the state), durational residency requirements, ineligibility of convicted felons, and disqualification of incumbents (term limits).