These are the members closest to the ideological center of the Senate and the House, according to National Journal's 2012 vote ratings. The members with composite scores closest to 50 are at the center of each chamber.
So who's in the center of the center? In the House, that distinction belongs to Michael Grimm, a Republican from New York, who was first elected in 2010 during the tea-party wave. However, once in Congress, Grimm did not join the Tea Party Caucus. Instead he aligned himself with the moderate Republican Main Street Partnership. In the Senate, now-retired Democrat Ben Nelson of Nebraska sits in dead center. Nelson was a moderate "blue dog" Democrat, opposing abortion but supporting health care reform.
Click on the graphic below for a larger view.
Graphic by Peter Bell; Text By Brian Resnick