History

• In 1787, the Constitutional Convention debated term lengths and classification of senators. The founders based the method of staggering seats on the congressional houses of state governments. The Delaware senate and the Pennsylvania unicameral congress featured three classes of senators, serving three-year terms rotated every year, while the governmental houses of New York and Virginia featured four-year terms with rotating classes of senators.
  
  

Senate Classes

• The United States Constitution specifies the staggering of congressional seats in Article 1 Section 3 Clause 2. As senate seats are six years long, every two years one-third of the senate seats are subject to election, either for incumbents seeking reelection or for non-incumbents running for open seats.
  
  

Benefits

• The Constitutional Convention hoped to achieve three goals by staggering congressional seats; the first goal was to bring stability to the senate and in turn, to other branches of government. The second goal was to prevent rapid turnover of senate seats which would change the entire structure of the government at once. Finally, staggering seats was meant to encourage deliberation, and attempt to discourage powerful congressional alliances from forming.