According to Article I, Section 3 of the U.S. Constitution, a senator must be 30 years of age, a citizen of the United States for 9 years, and must reside in the state he or she represents at the time of election.
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While the Articles of Confederation set no qualifications for delegates to the Continental Congress, the delegates at the 1787 Constitutional Convention supported establishing membership limitations for House and Senate members rather than leaving that task to the individual states. Influenced by British and state precedents, they established age, citizenship, and inhabitancy qualifications for senators, but voted against proposed religion and property requirements.
Age: The Constitutional framers debated the minimum age for representatives before they considered the same qualification for senators. Although James Wilson stated that "there was no more reason for incapacitating youth than age, where the requisite qualifications were found," other delegates were in favor of age restrictions. They were familiar with England's law requiring members of Parliament to be twenty-one or older, and lived in states which either barred legislators under the age of twenty-one or twenty-five from the upper chambers.
As introduced in May 1787, James Madison's Virginia Plan left Senate age restrictions to the delegates to decide, only stating that members of the second branch must "be of the age of ____ at least." Without debating the subject further, delegates voted in favor of filling the blank with thirty, and passed the clause unanimously on June 25, three days after designating twenty-five as the minimum age for representatives. In Federalist Paper No. 62, Madison justified the higher age requirement for senators. By its deliberative nature, the "senatorial trust," called for a "greater extent of information and stability of character," than would be needed in the more democratic House of Representatives.
Citizenship: Under English law, no person "born out of the kingdoms of England, Scotland, or Ireland" could be a member of either house of Parliament. While some delegates may have admired the "strictness" of this policy, no framers advocated a blanket ban on foreign-born legislators. Instead, they debated the length of time members of Congress should be citizens before taking office. The states' residency qualifications offered moderate guidelines in this regard. New Hampshire's state senators needed to be residents for at least seven years prior to election. In other states, upper house members fulfilled a five, three, or one-year requirement, while state representatives completed a residency period of one to three years.
Madison's Virginia Plan made no mention of citizenship when it was introduced to the convention in May. Two months later, the Committee of Detail reported a draft of the Constitution. Article V, Section 3 included a four-year citizenship requirement for senators. On August 9, Gouverneur Morris moved to replace the four-year clause with a fourteen-year minimum. Later that day, delegates voted against citizenship requirements of fourteen, thirteen, and ten years before passing the nine-year provision, making the Senate requirement two years longer than that for the House of Representatives.
At the convention, delegates viewed the nine-year citizenship qualification as a compromise "between a total exclusion of adopted citizens" and an "indiscriminate and hasty admission of them." While they were concerned that the Senate, especially, might be subject to foreign influence, they did not wish to close the institution to naturalized citizens of merit. Two foreign-born framers expressed these opposing considerations. According to Pierce Butler, recent arrivals were dangerously attached to their countries of origin, a particular concern for senators whose role would include the review of foreign treaties. From his own experience, he believed that naturalized citizens would need sufficient time to learn and appreciate American laws and customs before they could serve in government. For James Wilson, however, lengthy citizenship requirements "discouraged and mortified" everyone they excluded. He agreed with Benjamin Franklin that a strict policy would hinder positive immigration and offend those Europeans who had supported the Revolutionary War. On August 13th, Wilson moved to reduce the Senate qualification by two years. Delegates rejected his motion and confirmed the nine-year requirement by an eight to three vote.
Inhabitancy: Although England repealed Parliament's residency law in 1774, no delegates spoke against a residency requirement for members of Congress. The qualification first came under consideration on August 6 when the Committee of Detail reported its draft of the Constitution. Article 5, Section 3 stated, "Every member of the Senate shall be...at the time of his election, a resident of the state from which he shall be chosen."
On August 8, Roger Sherman moved to strike the word "resident" from the House version of the clause, and insert in its place "inhabitant," a term he considered to be "less liable to misconstruction." Madison seconded the motion, noting that "resident" might exclude people occasionally absent on public or private business. Delegates agreed to the term, "inhabitant," and voted against adding a time period to the requirement. The following day, they amended the Senate qualification to include the word, "inhabitant," prior to passing the clause by unanimous consent.
