Classes of U.S. Senators

The three classes of US Senators, each currently including 33 or 34 Senators (since Alaska became the 50th state in 1959, and until another state is admitted to statehood), are a means used by the US Senate for describing the schedules of Senate seats' elections, and of the expiration of the terms of office of the Senators holding the respective seats.

The US Constitution specifies staggered 6-year terms for Senators, and there are special provisions for getting a new state into a situation that makes that pattern continue automatically:

• around the time of the first Federal elections, in 1788, each state appointed its two Senators for, respectively,
  • a two-year and a four-year term,
  • a four-year and a six-year term, or
  • a two-year and a six-year term;
• upon the expiration of a Senator's term of any length, someone starts a new six-year term as Senator (based on appointment in most states, until a Constitutional amendment required direct popular election of Senators);
• when a new state is admitted to the Union, its two Senators have terms that correspond to those of two different classes, among the three classes defined below;
• which two classes is determined by a scheme that keeps the three classes as close to the same size as possible, i.e., that avoids any class differing by more than one from the minimum-sized class.

(This means at least one of a new state's first pair of Senators has a term of less than six years, and one term is either two or four years shorter than the other.)

(This offers a trivia question about the assignment of Senate seats to states admitted or readmitted during the Civil War and the Reconstruction period following it, in view of seats previously assigned to states initially in rebellion and then awaiting so-called "reconstruction" of their democratic institutions. Chance may have made the classes lopsided, and if so, a decision must have been made on whether to use new and readmitted states' Senate classes to reduce such an imbalance as quickly as possible, and whether therefore Confederate states' Senators' classes were, upon readmission, the same as, or in some cases different from, those before secession. Wikipedia offers the means of researching this.)

As of 2004:

• Class I consists of
  • the 33 current Senators whose seats are scheduled for re-election in November of 2006, 2012, and so on, and thus whose terms end in January of 2007, 2013, etc.
  • and the earlier Senators with terms ending in 2001, 1995, etc., back to 1791; and
  • some Senators in the class are indirect successors to Senators who started two-year terms in 1789.
• Class II consists of
  • the 33 current Senators whose seats are scheduled for re-election in November of 2008, 2014, and so on, and thus whose terms end in January of 2009, 2015, etc.
  • and earlier Senators with terms that ended in 2003, 1997, etc., back to 1793; and
  • some Senators in the class are indirect successors to Senators who started four-year terms in 1789.
• Class III consists of
  • the 34 current Senators whose seats are scheduled for re-election in November of 2010, 2016, and so on, and thus whose terms end in January of 2011, 2017, etc.
  • and earlier Senators with terms that ended in 2005, 1999, 1993, etc., back to 1795; and
  • some Senators in the class are indirect successors to Senators who started six-year terms in 1789.

External links

• US Senate class page (http://www.senate.gov/general/resources/pdf/senators_by_class.pdf)