The first session of the 114th Congress was slightly more polarized than the 113th Congress. However, what is important about the polarization graph below is the impact of the last three elections 2010, 2012, and 2014, on the Republican Party. The large influx of “Ted Cruz” Republicans has caused polarization to jump sharply from the first two years of President Obama’s first term. Polarization in the House may have leveled off (see below) but the Senate increase is much larger than the House. These results are from our final set of Weekly CS DW-NOMINATE Scores where the House and Senate are scaled together and each unique member of Congress receives a single score on the first and second dimensions.
The figure below shows the means of the two parties in each Chamber over time. For the most part the Senate means are more to the interior than the House means (the bright blue and bright red lines) but not always. In the last two elections, the Republican caucus in the Senate has become as conservative as the Republican caucus in the House. In contrast, Democratic Senators are clearly more moderate than their House counterparts.
Given how extreme Republican primary voters have evidently become (the base of the Party), it should be no surprise that a steady movement to the Right by Republicans coupled with the emergence of talk radio and now various social media platforms, that the Presidential nominating process has been “hijacked” by the extremes. In short, we may finally becoming to the end of the polarization that began in the 1970s simply because the Republican Party may fracture in 2016.