Paul Ryan is no one's idea of a moderate, but one thing his supporters emphasize is that he's willing and eager to work with Democrats and liberals. He and Democratic Sen. Ron Wyden released a policy paper on Medicare together.. Before that he worked on a separate Medicare proposal with Clinton budget director Alice Rivlin. It's enough to make Michael Tanner of the Cato Institute dub Ryan a "classic 'half a loaf' type of conservative."

Is this really true, though? To find out, political scientist Jordan Ragusa looked at two metrics to see how Ryan's record of bipartisanship compares to that of other House Republicans. First he measured the extent to which Ryan voted with the majority of the Republican caucus on partisan issues (that is, votes where half or more Republicans voted the opposite of half or more Democrats). Ragusa found that Ryan's record of party-line voting was barely distinguishable from that of a typical House Republican.

Source: Jordan Ragusa

The red line is the GOP average party unity score and the blue line is Ryan's score, from entering the 106th Congress in 1999 to the 111th Congress, which ended in 2011. Ryan's voting record was slightly less partisan than the overall GOP caucus until Democrats retook the House in 2007, after which Ryan began formulating his "Roadmap" proposals and grew more partisan than the typical House Republican.

Ragusa also looked at bill cosponsorships to measure what percentage of the House members cosponsoring Ryan's bills were Republicans. The figure is about 72 percent, which, Ragusa notes, is smack dab in the middle of House Republicans. What's more, Ryan's Democratic cosponsors tend to flock to less partisan bills, like one to promote homeownership among veterans, a bill with then-Rep. Ben Cardin (D-Md.) to change the tax treatment of college housing, and, of course, Ryan's bill changing the tax treatment of arrow components, which Utah Democrat Jim Matheson backed as well.

The only major proposal of Ryan's to gain Democratic support was the line-item veto, which has been supported by both parties since at least the Clinton administration. His proposals to privatize Social Security, end the Fed's unemployment mandate and cut investment taxes, not to mention his budgets, have garnered no Democratic backers.

Is Ryan's level of partisanship unusual? Not among House Republicans certainly. But then again, the level of partisanship among both parties in the House is historically high. As political scientists Nolan McCarty, Keith T. Poole, and Howard Rosenthal have shown, the share of members voting party-line hasn't been higher since the Gilded Age.

Source: McCarty, Poole and Rosenthal.

This isn't just a drop in collegiality. It's mostly that Congress has truly grown more ideologically divided - or, more precisely, House Republicans have gotten a lot more conservative while Democrats have largely stayed still.

Source: McCarty, Poole and Rosenthal.

In other words, this isn't just a Ryan problem. He's grown more conservative and partisan at roughly the same rate that Congress has, but he's not exactly a poster boy for bipartisanship either.