The qualifications required to hold the office of U.S. Senator or Representative to Congress are established and set out within the U.S. Constitution. These constitutional qualifications are the exclusive qualifications for congressional office, and may not be changed or added to by Congress, nor may these qualifications be added to or changed unilaterally by a state. There are only three "positive" standing qualifications for the office of U.S. Senator and Representative: Age—a Representative to Congress must be at least 25 years old; a Senator must be at least 30 years old. Citizenship—a Representative must be a citizen of the United States for at least seven years; a Senator must be a citizen of the United States for at least nine years. Inhabitancy—a person elected to the House or Senate must be an "inhabitant" of the state from which chosen "when elected." Although there may have been some credible minority argument concerning the ability of Congress or the states individually to set additional or different qualifications for federal office from those set out in the Constitution, it is now well-settled that the qualifications established in the U.S. Constitution are the exclusive qualifications for federal office (and are not merely "minimum" qualifications). The constitutional history and case law demonstrate that such constitutional qualifications are fixed and may not be changed, added to, or subtracted from by Congress, nor by the state legislatures (other than by an amendment to the U.S. Constitution). The history of the adoption of the qualifications provisions within the Constitution demonstrates a philosophic commitment of the framers to minimal qualifications for congressional office, fixed in the federal Constitution, as an underlying principle of republican government. In warning against an "uncontrollable power over the elections to the federal government" either in the state legislatures or in the federal government itself, Alexander Hamilton, in an oft-quoted comment from the Federalist Papers , explained that, "The qualifications of the persons who may ... be chosen ... are defined and fixed in the Constitution, and are unalterable by the legislature." Similarly, James Madison argued at the Constitutional Convention of 1787 for very minimal required qualifications for Congress that "ought to be fixed by the Constitution," as a means to prevent infringement on the free choice of the people of whom they wish to have represent them, and as a way of preventing "an aristocracy or oligarchy ... by limiting the number capable of being elected." Madison expanded on the premise of minimal qualifications of those being chosen by the people for Congress as a means of preserving the "principles of republican government," discussing those who the people may choose for Congress: Who are to be the objects of popular choice? Every citizen whose merit may recommend him to the esteem and confidence of his country. No qualification of wealth, of birth, of religious faith, or of civil profession is permitted to fetter the judgment or disappoint the inclination of the people. The qualifications for congressional office were thus intentionally kept to a minimum by the framers to empower the electorate, and to promote the "fundamental" democratic principle that in the new republic "the people should choose whom they please to govern them." One constitutional scholar has noted that in setting minimal qualifications in the Constitution in 1787 and "barr[ing] both Congress and states from adding statutory property qualifications—or any other qualifications for that matter—to Article I's short list of age, residency, and citizenship," the "federal Constitution positioned itself on the democratic frontier" for its time, in comparison even to the provisions in the colonial legislatures: A man of merit and repute who owned little or no property—say, a minister, schoolmaster, or war hero—could serve as a federal representative even though eleven states would have barred him from their own lower houses. The commitment of the framers to minimal qualifications to hold elective office in Congress, the Supreme Court has noted, was to further the fundamental principle of electoral choice, and that "this broad principle incorporated at least two fundamental ideas." "First, we emphasized the egalitarian concept that the opportunity to be elected was open to all." Secondly, "we recognized the critical postulate that sovereignty is vested in the people, and that sovereignty confers on the people the right to choose freely their representatives to the National Government." Modern-era Supreme Court cases have affirmed that "the Framers intended the Constitution to be the exclusive source of qualifications for Members of Congress, and that the Framers thereby 'divested' States of any power to add qualifications." The qualifications for federal office established in the U.S. Constitution were intended to be uniform and consistent across the nation, and may not be changed unilaterally by one state such that they would differ from state to state. As to any authority of the states over federal offices which are established in the U.S. Constitution, the Supreme Court in U.S. Terms Limits, Inc., and again in Cook v. Gralike, explained that whatever authority the states have over qualifications and elections of federal officers must be a "delegated" authority arising, as does the national government, "from the Constitution itself," and could not be a "reserved" power of the states (under the Tenth Amendment), since a state could not "reserve" a power which it never possessed, that is, the states could not have "reserved" a power relative to something which did not exist before its creation in the Constitution. As explained by the Supreme Court, Because any state authority to regulate election to ... [federal] offices could not precede their very creation by the Constitution, such power "had to be delegated to, rather than reserved by, the States." The individual states may not, therefore, establish their own (and potentially varying) qualifications for the office of U.S. Senator or Representative. State laws which have attempted to place requirements on candidacies to Congress that have been deemed to constitute "additional qualifications" to be elected to federal office, such as, for example, requirements of residency in the congressional district from which one is running (for the House of Representatives), disqualification from office of certain convicted felons, additional residency requirements for one to be an "elector" qualified to run for congressional office (or other durational residency requirements), or the disqualification for certain long-term incumbents (term limits), have been found to be unconstitutional when challenged. The U.S. Constitution, at Article I, Section 5, clause 1, expressly delegates to each house of Congress the authority to judge the qualifications for office of its own Members: "Each House shall be the Judge of the Elections, Returns, and Qualifications of its own Members.... " As noted by authorities on parliamentary democracies and the Constitution, since Congress is an independent, separate, and co-equal branch of government, it would not be consistent with its status or functions, nor with the separation of powers principles generally, for a different branch of the government, such as the judiciary, to determine the legislature's make-up: The propriety of each House being the judge of these matters is very obvious. No power external to the House could decide them without an intrusion upon the question of its organization, which would be fatal to its freedom and independence. The right of the House, as a body, to determine upon the right of each member to a place in that body is so obvious that it needs no comment. The power of election is vested, as we have seen, in the constituency under the laws of the States; but whether that constituency have elected qualified persons, and whether the officers holding the election have made proper returns, is left to the House in order to prevent intrusion of persons disqualified or not duly elected upon their deliberations. Justice Joseph Story explained the purpose behind the constitutional authority to judge the elections and returns of each House's own members: It is obvious that a power must be lodged somewhere to judge of the elections, returns, and qualifications of the members of each house composing the legislature; for otherwise there could be no certainty as to who were legitimately chosen members, and any intruder or usurper might claim a seat, and thus trample upon the rights and privileges and liberties of the people. ... If lodged in any other, than the legislative body itself, its independence, its purity and even its existence and action may be destroyed, or put into imminent danger. The courts have thus indicated that the House or the Senate, respectively, and not the courts, would be the proper forum for a challenge concerning the qualifications of one to be a Member of Congress. The Supreme Court in Barry v. Cunningham , for example, stated that, "The Senate [has the] sole authority under the Constitution to judge of the elections, returns and qualifications of its members ..." and "to render a judgment which is beyond the authority of any other tribunal to review." In Seville v. Elizalde, the U.S. Court of Appeals for the District of Columbia Circuit found the following: We are cited no cases, and we find none, in which the Federal courts have ever been asked to determine the qualifications of a member of Congress. Apparently, it has been fully recognized that that power is lodged exclusively in the legislative branch. In a case concerning a challenge to the results of a congressional election, then-Judge Scalia writing the opinion of the U.S. Court of Appeals for the District of Columbia Circuit, found that the court need not rely on the "amorphous and partly prudential" political question doctrine to abstain from ruling on the matter.