Fewer moderates running for Congress means a more polarized Capitol Hill

The 113th Congress is, by the numbers, shaping up as one of the least productive ever, and a new study suggests that the problem may be less with the people than the pipeline.

Potential centrist candidates of both parties at the state level are increasingly finding the jump to Congress an unattractive option, feeling that a House or Senate seat in Washington is not a promising path to achieving their policy goals. With state legislators acting as the traditional “pipeline” supplying candidates for Congress, the result is that more ideological candidates are nominated and political polarization is on the rise, according to Danielle Thomsen, a political science fellow at Duke University.

“This makes it very difficult to conceive of a Congress where representatives are all of a sudden going to occupy the political center again,” Ms. Thomsen said in a phone interview.

The study looked at the decisions of state legislators around the country on a possible congressional race.

“This is where a lot of members of Congress are coming from, so it makes them the most likely population to weigh a run,” Ms. Thomsen said.

The article, published in the July edition of the Journal of Politics, used data from the Candidate Emergence Study begun in 1998, which polled 262 Republican and 307 Democrat state legislators to determine long-term trends in decisions to run for Congress.

The article also used a data set of FEC filings from 2000 to 2010 that tracked the ideology of all state legislators from the period, whether or not they ran for Congress. This second set of data also showed a large growth in the disparity between the ideologies of the two parties over the decade.

For both Republicans and Democrats, moderate state legislators were less likely to attempt a run for national congressional office, according to the data.

However, the discrepancy was much higher among Republicans — moderates in that party were about nine times less likely to run than their more conservative GOP compatriots.

Tellingly, the study also found that potential Republican candidates closer to the ideological center didn’t value a seat in Congress as highly as a more conservative Republican might. Party moderates were less likely to believe their policy goals would be achieved in Congress, and thus didn’t see the same importance in a congressional seat.

The study did not, however, find that Democrats across the ideological spectrum were more or less likely to value a congressional seat. Ms. Thomsen said her findings support the theory of a larger trend of “asymmetric polarization” in American politics, in which both parties have moved away from the center, but Republicans have moved further to the right than the Democrats have moved to the left.

Additionally, Republicans are much more uniform in their beliefs than Democrats, another factor that may scare off Republican moderates — who themselves have become outliers as the party’s center of gravity moves right — from congressional runs.

“Both the parties were much less homogenous in the 1950s,” Ms. Thomsen said, “but the Republican Party has grown particularly more homogenous in their ideology since then.”

Though not included in this study, Ms. Thomsen has also studied and interviewed moderate congressional members who opted to retire from their seats. She said that the pressure on moderates has become stronger than ever as the political center weakens.

“There was a lot of pressure put on them to toe the party line, not just by party leadership but also by rank-and-file members,” Ms. Thomsen added. “These members were less likely to feel like they were going to get things done or that their policy goals would be achieved.”

Projecting into the future, Ms. Thomsen suggests that the factors affecting both ends of the congressional pipeline — both moderates choosing to retire and moderates choosing not to run — will only make partisanship more toxic in the years to come.

“I think this doesn’t bode well for the political center and its representation in Congress,” she added.

The study is only the latest in a mountain of academic research that suggests partisan members of the American political process are becoming more active and more extreme.

“[M]any of those in the center remain on the edges of the political playing field, relatively distant and disengaged, while the most ideologically oriented and politically rancorous Americans make their voices heard through greater participation in every stage of the political process,” a June study from the Pew Research Center said.

However, as ideological divisions widen on Capitol Hill, a plurality of Americans fall in the middle of the road ideologically, with 42 percent of voters identifying themselves as “moderate,” 33 percent as “conservative,” and 22 percent as “liberal.”