United States Senate

===Qualifications===
{{United States Senate}}
[[Article One of the United States Constitution|Article I, Section 3, of the Constitution]], sets three qualifications for senators: (1) they must be at least 30 years old; (2) they must have been citizens of the United States for at least nine years; and (3) they must be inhabitants of the states they seek to represent at the time of their election.<ref>{{Cite journal |title=Article 1, Section 3 |url=https://constitution.congress.gov/browse/article-1/section-3/ |journal=Constitution of the United States}}</ref> The age and citizenship qualifications for senators are more stringent than those for representatives. In [[Federalist No. 62]], [[James Madison]] justified this arrangement by arguing that the "senatorial trust" called for a "greater extent of information and stability of character":

<blockquote>A senator must be thirty years of age at least; as a representative must be twenty-five. And the former must have been a citizen nine years; as seven years are required for the latter. The propriety of these distinctions is explained by the nature of the senatorial trust, which, requiring greater extent of information and stability of character, requires at the same time that the senator should have reached a period of life most likely to supply these advantages; and which, participating immediately in transactions with foreign nations, ought to be exercised by none who are not thoroughly weaned from the prepossessions and habits incident to foreign birth and education. The term of nine years appears to be a prudent mediocrity between a total exclusion of adopted citizens, whose merits and talents may claim a share in the public confidence, and an indiscriminate and hasty admission of them, which might create a channel for foreign influence on the national councils.<ref name="fed62">[https://guides.loc.gov/federalist-papers/text-61-70 Federalist Papers, No. 62] {{Webarchive|url=https://web.archive.org/web/20211123012140/https://guides.loc.gov/federalist-papers/text-61-70 |date=November 23, 2021 }}, Library of Congress.</ref></blockquote>

The Senate (not the judiciary) is the sole judge of a senator's qualifications. During its early years, however, the Senate did not closely scrutinize the qualifications of its members. As a result, four senators who failed to meet the age requirement were nevertheless admitted to the Senate: [[Henry Clay]] (aged 29 in 1806), [[John Jordan Crittenden]] (aged 29 in 1817), [[Armistead Thomson Mason]] (aged 28 in 1816), and [[John Eaton (politician)|John Eaton]] (aged 28 in 1818). Such an occurrence, however, has not been repeated since.<ref>{{cite web|url=https://www.senate.gov/artandhistory/history/minute/Youngest_Senator.htm|title=1801–1850, November 16, 1818: Youngest Senator|access-date=November 17, 2007|website=United States Senate|archive-date=December 26, 2002|archive-url=https://web.archive.org/web/20021226155950/https://www.senate.gov/artandhistory/history/minute/Youngest_Senator.htm|url-status=live}}</ref> In 1934, [[Rush D. Holt Sr.]] was elected to the Senate at the age of 29; he waited until he turned 30 (on the next June 19) to take the oath of office. In November 1972, [[Joe Biden]] was elected to the Senate at the age of 29, but he reached his 30th birthday before the swearing-in ceremony for incoming senators in January 1973.

The [[Fourteenth Amendment to the United States Constitution]] disqualifies as senators any federal or state officers who had taken the requisite oath to support the Constitution but who later engaged in rebellion or aided the enemies of the United States. This provision, which came into force soon after the end of the Civil War, was intended to prevent those who had sided with the [[Confederate States of America|Confederacy]] from serving. That Amendment, however, also provides a method to remove that disqualification: a two-thirds vote of both chambers of Congress.<ref>{{Cite journal |title=Fourteenth Amendment |url=https://constitution.congress.gov/browse/amendment-14/#14_S1 |journal=Constitution of the United States}}</ref>