Graph: Republican Hyper-Partisanship and the Hyper-Polarization Of Congress

Announcing her intention to retire yesterday, Sen. Olympia Snowe (R-ME) decried the “atmosphere of polarization” that she finds “frustrating.” While Snowe didn’t assign responsibility for the current climate of hyper-partisanship in Congress, a study by distinguished political science professor Keith Poole does. It should come as no surprise that the analysis finds Republicans are to blame for the gridlock.

Poole assessed all of the Republican and Democratic votes in the House and Senate from 1879 to 2011, and plotted both parties on a liberal to conservative axis. Poole’s study shows that beginning right around 1980, House Republicans began to vote in strict partisan lines considerably more than Democrats.

Note on the graph: The closer to 1.0, the more partisan that members’ votes were that year. The 10th percentile line represents a moderate member of Congress, while the 90th percentile line represents a member of Congress who, for example, is 90% more conservative than the his/her co-partisans.

The graph shows that the Democrats have barely edged towards the left over the last 30 years, while both moderate and partisan House Republicans have veered way off to the extreme right. For instance, the partisan Republican (the “90% Republican”) in 2011 is hovering near the absolute threshold of the radical right. In comparison, the partisan Democrat (the “90% Democrat”) is far from his/her ideological extreme, having only made a negligible move to the left in the last 30 years. Even more critical is that a moderate Republican in 2011 (the “10% Republican”) is not really moderate anymore, having moved so far to the right that he/she is nearly as factional as the Democrat’s partisan member.

Poole’s study shows that House Republicans are more to blame than House Democrats for the lack of bipartisan compromise and overwhelming polarization that currently characterizes Congress. And considering Congress’s approval rating is 11% — lower than BP during its oil spill in 2010 — the American people are clearly fed up.