Ideology in the House of Representatives: How Polarized is Congress Really?

Ideology in the House: What's the Real Story?A number of political advocacy organizations need Americans to think of Congress in dire and extreme terms in order to attract donations and advance their particular causes. As Bill Nissim advises non-profit organizations:

“The human mind can only attach one specific meaning or feeling to an item. Although the overall perception of that item represents a culmination of all of its attributes, we really only remember one distinct thing…. Is your message clear and compelling?… The by-products of your messaging should be passion and action. Does your message invoke passion and action?”

“Polarized and Politicized,” the ACLU declares of religious policy matters in a message tied to a fundraising appeal. The Campaign for America’s Future tapped into this vein of thinking in a summer breakout session, “The Congressional Fix: Can Congress Work in Polarized Age?”

But how polarized is American politics really? Is the Congress really divided into two firmly and diametrically opposed camps? If we listen to the fundraisers talk, we might think so. In conservative fundraising appeals, even the most centrist Democrat on Capitol Hill is on the political fringes; in liberal appeals each and every Republican legislator is on the feathertip of the right wing. If we believe them both, the Congress looks like this:

Congressional Polarization in Idealized Form: What two polar opposites would look like

If we took a set of policies that exemplified political liberalism, members of Congress could be ranked as 0% to 100% liberal based on how much of the liberal policy slate they supported during this current 111th Congress of 2009-2010. Conversely, we could take a set of policies exemplifying political conservatism and rank members of Congress as 0% to 100% conservative. Subtracting the conservative score from the liberal score, we’d arrive at one net measure, with perfect liberals (who are never conservative) having a score of positive 100 and perfect conservatives (who are never liberal) having a score of negative 100. The above graph is a hypothetical, idealized representation of the 111th Congress, one in which the 255 Democrats are all perfect liberals, the 178 Republicans are all perfect conservatives, with a gaping chasm of ideology separating the two.

Here at That’s My Congress, we’ve spent the last two years classifying on dozens of bills as emblematically liberal or conservative and assembling voting and cosponsorship information for those bills into exactly the sort of congressional score described above. Moving away from the idealized world of polar opposition as described by the fundraising set, where do members of Congress actually lie along the ideological spectrum?

Congressional Action Scores in the House of Representatives, 2009-2010: Ideology in Congress along a spectrum

The above is a graph of net congressional scores for all 433 current members of the House of Representatives (2 seats are currently vacant), based on a slate of legislation available for review here. The y-axis refers to the number of representatives at a certain score; for instance, there are 13 members of Congress with a score of 44 and also 13 members of Congress with a score of -38. The actual graph of congressional ideology noticeably differs from the idealized graph. What can we say about ideology in the 111th Congress?

1. The House of Representatives is far from perfectly polarized. There are far more members of Congress whose scores lie in between +50 and -50 than members of Congress whose scores lie farther out on either end.

2. No member of Congress is a perfect liberal or a perfect conservative. No member of Congress has supported the entirety of either the liberal or the conservative slate. Although most representatives who fall on the conservative end of the spectrum have failed to support a single liberal policy, a number of representatives who fall on the liberal end of the spectrum have supported one or more conservative policies.

3. Ideology in Congress is imperfectly but strongly correlated with party. None of the 178 Republicans have attained a net congressional score on the liberal side of the policy spectrum; the most liberal Republican in the Congress is Charles Djou of Hawaii, who has a net score of -1. Seventeen of the 255 Democrats in Congress have attained a net conservative score. The most conservative record by a Democrat is attained by Bobby Bright of Alabama, who has a net score of -44.

4. The distribution of ideology in the Congress is bimodal. There are two centers in the Congress, not one. Those on the liberal side of the ideological spectrum have a mean score of +36.1 and a median of +37. Those on the conservative side of the ideological spectrum have a mean score of -43.4 and a median of -45. For both groups, the median and the mean are close to one another, suggesting an even distribution on either side of the mean. For both groups, the typical member does not support a majority of her group’s ideological slate.

This review of legislation makes clear that the Congress is neither monolithic nor divided into two rigidly obedient sects. The Congress can reasonably be divided into two ideological bodies, but those bodies are not perfectly defined by political party and the extent of adherence to ideological slates varies widely. The behavior of a liberal Democrat is distinct from the behavior of a conservative Democrat, and the behavior of a mildly conservative Republican is distinct from the behavior of a rigidly conservative Republican.

These empirical patterns may not fit well into the template of a fundraising letter; it may be time to step out of that template altogether.

One Comment

on “Ideology in the House of Representatives: How Polarized is Congress Really?
One Comment on “Ideology in the House of Representatives: How Polarized is Congress Really?
  1. It’s worth noting that the most ideologically conservative Republican members of the House are further away from the center than the most ideologically liberal Democratic members of the House. The Republicans skew more toward the extreme than the Democrats.

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