An examination of the results of the recent midterm elections indicates that the new House of Representatives will probably be the most conservative and ideologically polarized House since the end of World War II. Republicans will hold 242 seats after a net gain of 63 seats, constituting the largest Republican majority in the House of Representatives since the 80th Congress (1947–49), which also had 242 Republican members.

Republicans picked up 66 House seats previously held by Democrats while losing only three of their own seats. Although Democrats lost seats in every region of the country, these losses were concentrated in marginally Democratic- and Republican-leaning districts that had voted for either John McCain or Barack Obama by a relatively narrow margin in the 2008 presidential election. Democrats did not lose a single district in which Obama received more than 57% of the vote in 2008. In fact, they gained three seats in these strongly Obama districts in 2010.

According to an analysis of all House roll call votes in 2009, the large majority of Democrats who represented marginally Democratic- and Republican-leaning districts in the 111th Congress were ideological moderates, based on their first dimension DW-NOMINATE scoresFootnote ¹. As a result, Democratic losses in 2010 came very disproportionately from the party's moderate wing. Of the 66 Democratic seats that switched to the GOP in 2010, 46 had been held by moderates, 18 had been held by moderate liberals, and only two had been held by very liberal Democrats.

In the aftermath of the midterm elections, the balance of power within the House Democratic caucus will likely shift considerably to the left. In the 111th Congress, moderate Democrats outnumbered very liberal Democrats by 71 to 66. In the 112th Congress, however, very liberal Democrats are projected to outnumber moderate Democrats by 66 to 25.

While Democratic losses in the House were heavily concentrated among members of the party's moderate wing, very few of the Republicans who will be replacing those Democrats are likely to be moderates. In fact, the already tiny number of moderate Republicans in the House will probably shrink in 2011, since two of the three GOP seats that switched to the Democrats were held by moderates.

To estimate the distribution of ideology in the new House of Representatives, I assigned newly elected members a liberal-conservative voting score based on the average score of members of their party from the same state or, when such a score could not be formulated, the average from a neighboring state, in the 111th Congress. This procedure may actually understate the conservatism of the newly elected Republicans, because it assumes that they will vote similarly to Republicans elected before the Tea Party movement emerged as a major force.

Figures 1a and 1b display, respectively, the liberal-conservative voting scores of Democratic and Republican representatives in the 111th Congress and the predicted liberal-conservative scores of Democratic and Republican representatives in the 112th Congress. The results indicate that the new House will be much more conservative and ideologically polarized than the old House. The location of the median member will shift from slightly left-of-center in the 111th Congress to significantly right-of-center in the 112th Congress as a result of the replacement of a large number of moderate Democrats with conservative or very conservative Republicans. In addition, the total number of moderates in the House—almost all of whom were Democrats—will shrink from 75 to 28. As a result, the ideological distance between the median Democratic representative and the median Republican representative will increase dramatically.

Figure 1a

Party and Ideology in the Old and New House of Representatives, 111th House, First Session (2009)

Figure 1b

Party and Ideology in the Old and New House of Representatives, 112th House (Projected)

Source. http://voteview.com/dwnomin.htm.

Just how conservative will the new House of Representatives be? An interesting comparison can be drawn with the House that was elected in 1994, the year in which Republicans won a majority of seats in the House for the first time in 40 years. Figure 2 displays the liberal-conservative voting scores of Democratic and Republican representatives in the House that elected Newt Gingrich as its Speaker and later forced a partial shutdown of the federal government when agreement could not be reached with then-President Clinton on the federal budget.

Figure 2

Party and Ideology in the 104th House (1995–1996)

Source. http://voteview.com/dwnomin.htm.

Figure 2 indicates that the 112th House is likely to be even more conservative than the Gingrich House of 1995–97. In the Gingrich House, moderate Republicans outnumbered very conservative Republicans by a wide margin. In the 112th House, however, very conservative Republicans will greatly outnumber moderate Republicans. Whereas moderate Republicans held the balance of power in the Gingrich House, they will have almost no influence in the 112th House. As a result, pressure on the House leadership to pursue a hard-line conservative agenda is likely to be much stronger in the new House than it was in the Gingrich House, and opportunities to reach bipartisan agreements with Democrats are likely to be much more limited, if not nonexistent.