In the 2008 elections, 29 incumbent senators ran for reelection. While running as an incumbent typically helps a Senate candidate, a senator's voting record can also be a liability during a campaign. Republican Senate incumbents faced an electorate generally dissatisfied with their party. Accordingly, some Republican senators had electoral incentives to distance themselves from their party, both in their rhetoric and in their Senate roll call votes. However, political parties provide strong incentives for senators to demonstrate party loyalty in their voting records. Most of the senators faced conflicting pressures as they approached the 2008 elections. In this study, I identify patterns in senators' partisan behavior, focusing on the interplay between senators' electoral and partisan incentives. I analyze data on Senate roll call votes from "Congressional Quarterly." I also assess the electoral climate of each Senate race in 2008 then compare these dynamics to variations in incumbents' voting behavior in the Senate. I then compare the patterns in partisan behavior I uncover leading up to the 2008 Senate elections with Senate roll-call voting data since 1991 to establish larger trends in election-based partisan behavior.