No Person shall be a Senator who shall not have attained to the Age of thirty Years, and been nine Years a Citizen of the United States, and who shall not, when elected, be an Inhabitant of that State for which he shall be chosen. [U.S. Constitution, Article I, section 3, clause 3]
Delegates to the 1787 Constitutional Convention established requirements that individuals had to meet in order to become a member of the House and Senate. Influenced by British and state precedents, they set age, citizenship, and inhabitancy qualifications for senators but voted against proposed religion and property requirements.
Age: James Madison's Virginia Plan called for a minimum age requirement for service in both the House and Senate but left it to the delegates to define that requirement. The framers were familiar with England's requirement that members of Parliament be 21 or older, and they lived in states that had higher age requirements to serve in their upper chambers.
The delegates voted on June 12 to set a minimum age of 30 for the Senate and later added a minimum age of 25 for serving in the House. They maintained that members of the Senate ought to be older and more experienced and, perhaps, wiser. In The Federalist, No. 62, Madison justified the higher age requirement for senators. By its deliberative nature, he contended, 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, none 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 residency qualifications of the various states offered some guidelines. In New Hampshire, for example, 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 residency requirement, while state representatives completed a residency period of one to three years.
The Virginia Plan made no mention of citizenship when Edmund Randolph introduced it to the convention in May. Two months later, when the Committee of Detail reported a draft of the Constitution, it included a four-year citizenship requirement for senators, one more than the proposed requirement for House members.
On August 8 the convention agreed to raise the House requirement to 7 years. The next day, Gouverneur Morris of Pennsylvania moved that the Senate's requirement be twice as long, 14 years. Charles Pinckney of South Carolina agreed with the longer requirement, arguing that "as the Senate is to have the power of making treaties & managing our foreign affairs, there is peculiar danger and impropriety in opening its door to those who have foreign attachments." Pierce Butler of South Carolina, himself born abroad, believed that naturalized citizens would need sufficient time to learn and appreciate American laws and customs before they could serve in government. James Wilson of Pennsylvania, another foreign-born delegate, argued that lengthy citizenship requirements "discouraged and mortified" everyone they excluded. He agreed with fellow Pennsylvanian Benjamin Franklin that a strict policy would hinder positive immigration and offend those Europeans who had supported the Revolutionary War.
Later that day, delegates voted against citizenship requirements of 14, 13, and 10 years before passing the nine-year provision, making the Senate requirement only two years longer than that for the House of Representatives. On August 13, Wilson moved to reduce the Senate qualification by two years, but delegates rejected his motion and confirmed the nine-year requirement by an 8 to 3 vote.
In Federalist, No. 62, James Madison defended the nine-year citizenship qualification as a compromise "between a total exclusion of adopted citizens" and an "indiscriminate and hasty admission of them."
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 of that draft 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 Connecticut's Roger Sherman moved to strike the word "resident" from the language dealing with requirements for members of the House 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.