The Senate was so polarized in 2013 that the Democratic senator who was the second most likely to oppose President Barack Obama was ... Majority Leader Harry Reid.
That's not to say the Nevadan actually opposed Obama at all. Rather, on 10 separate votes on which the president had a clear position included on the CQ Roll Call scorecard, Reid voted no for procedural reasons. Being on the prevailing side of a vote allowed Reid to enter a motion to reconsider, preserving the opportunity to call it up again later.
That was also the case on Obama's three nominations to the D.C. Circuit Court of Appeals. When the Senate initially voted to limit debate on each of those individual nominations, Republican opposition led to them falling short of the 60 votes that were needed to cut off debate at the time.
The desire of Democrats to fill the D.C.-based appeals court led to the deployment of the "nuclear option," changing the Senate's precedents on nominations with a simple-majority vote.
Only Sen. Mark Pryor of Arkansas, considered among the most vulnerable incumbent Democrats in the 2014 cycle, opposed Obama's stated positions more frequently than Reid. Pryor went against the president on 10.3 percent of the votes, with Reid at 9.6 percent, followed closely by West Virginia Democrat Joe Manchin III at 9.5 percent.
CQ Roll Call has prepared a series of charts showing the changes in voting patterns over time. Congressional Quarterly began tracking presidential support during the administration of President Dwight D. Eisenhower. The complete vote studies package is available in the current edition of CQ Weekly and to subscribers of CQ.com here .