The graphs above plot each member of the House and Senate according to two variables: party unity (how often a member voted with his or her own party) and presidential support (how often a member voted in support of the president's position). Members who participated in less than a quarter of roll call votes in a given year are not included in that year's distribution.
In 2012, Democratic Rep. Jim Matheson of Utah opposed his own party more frequently than any other member, voting with the Democrats on only 32 percent of votes that divided the two parties. On the Senate side, Republican Scott P. Brown dissented from the party line most frequently with a party unity score of 38 percent. While Matheson's independence helped him narrowly win re-election in a conservative district, Brown was not able to hold on in blue Massachusetts.
House Republicans were strongly opposed to President Obama's agenda last year in a pattern reminiscent of Democratic opposition to George W. Bush in 2007. The vast majority of GOP members had 2012 presidential support scores of 25 percent or lower. Only two Democrats fell in that same range: Mike McIntyre of North Carolina and Collin C. Peterson of Minnesota, both of whom won re-election.
Oddly, Obama's most frequent supporters in the Republican House last year were libertarian-leaning Justin Amash of Michigan and Ron Paul of Texas, usually because the president had objected to spending cuts and they voted no, saying their party wasn't cutting enough. Obama's top Republican supporters in the Senate were a triad of more traditional moderates: Brown of Massachusetts along with Susan Collins and Olympia J. Snowe of Maine.
Interactive by Ted Benson
About the Data
CQ Roll Call bases its vote studies on all floor votes for which members were asked to vote “yea” or “nay.” In 2012 there were 657 such roll call votes in the House and 251 in the Senate.
Editors select presidential support votes each year based on clear statements by the president or authorized spokesmen. Support scores represent the percentage of roll call votes on which members of Congress voted in agreement with the president’s position.
Roll call votes used for the party unity study are those on which a majority of Democrats opposed a majority of Republicans. Party unity scores indicate the percentage of the time that members voted in agreement with the majority of their party on such party unity votes.