Danger: Feverish Senate ahead (Andrew Harrer/Bloomberg News).

Washington Postreporter Paul Kane this week offers a superb look inside the Senate at the “intensely personal war” between Senate Majority Leader Harry M. Reid (D-Nev.) and Minority Leader Mitch McConnell (R-Ky.)  That leadership war, Kane reports, has “almost immobilized the Senate,” and is no doubt fueled in part by the approaching midterm elections in which control of the Senate is at stake. Rising partisanship coupled with intense electoral competition has brought the Senate to a near halt.

Kane importantly puts the current partisan deadlock in context, noting that the current situation “is just an escalation of an old problem.” I agree. Still, I think it’s worth a second look at just what is old and what is new about the current Senate impasse.

First, what is old?  Our usual Senate metrics make plain that the Senate’s difficulties this year reflect an escalation of previous procedural warfare on the Senate floor.  Below, I show counts of the number of cloture motions filed, voted on and invoked annually, starting in 1973 and running through June of 2014.  As I’ve noted previously, cloture counts are imperfect measures of filibusters. But they’re good proxies for capturing the Senate’s parliamentary knots. True, sometimes majority leaders might file cloture motions to lend some predictability to Senate floor debate; more often of late, majority leaders file cloture when they can’t secure consent of their minority party colleagues  to bring a matter to a vote. Reid’s difficulties are seen pretty starkly if we calculate the number of cloture motions filed per month (to control for the half-year of 2014 data): in 2013, Reid filed on average just seven cloture motions per month; so far this year, typically unable to secure GOP consent, he’s felt compelled to more than double that rate to roughly 16 motions per month.

Senate cloture motions, 1973-present; data from U.S. Senate, graph by Tara Kutzbach

Raw counts, however, don’t tell us much about the partisan character of the Senate’s procedural mess. The figure below shows a measure of party differences on cloture votes.  The metric used here is the difference between the percentage of majority party senators voting yea and the percentage of minority party senators voting yea. (If 80 percent of the majority party and 20 percent of the minority party vote in favor of cloture, the difference is 60 percent.) Each cloture vote is represented by a black dot; the red line shows the smoothed trend line over the 40-year period.

Graph by Sarah Binder, data from U.S. Senate.

Many cloture votes have been nearly straight party-line votes in recent years (see the clustering of black dots near the 1.0 mark).  Moreover, procedural partisanship has more than doubled since the 1970s.  Average party difference on cloture votes in 1973 was roughly 30 percent; so far in 2014, partisanship averages 80 percent.  Even since last year, partisanship has increased 10 percent.  Given the 60-vote threshold for cloture on legislative matters, rising partisanship throws the Senate out of gear.

Second, what then is new about the Senate’s procedural mess?  Stalemate over policy coupled with Republican anger over the Democrats’ nuclear move last fall to lower the threshold for cloture on nominations has left a very small window, one that even overwhelmingly bipartisan bills often can’t get through.  Instead, Senate Democrats have focused on confirming Obama’s appointees for executive and judicial vacancies.  That nearly singular focus on nominations is visible in the figure below that shows the percentage of all cloture motions that were filed on nominations (rather than legislative measures and motions).   This year’s experience is not unprecedented.  Still an overwhelmingly high percentage of cloture motions are targeted to nominations.

Percent of cloture motions filed on nominations; graph by Sarah Binder, data from U.S. Senate.

Those data however belie the deep partisanship that envelops the Senate this year (and drives Harry Reid nuts) on nominations.  As the figure below demonstrates, we see party-line votes (in red) on nearly every cloture vote taken on judicial nominations this Congress.  Of course, with the nuclear move, Democrats can invoke cloture without GOP help. But after forcing Democrats to secure cloture, Republicans then typically further punish the Democrats by refusing to yield post-cloture consideration time for the nominees (two hours for trial judges, 30 for appellate).  And when confirmation votes (in blue) take place, most judicial nominees are confirmed with GOP support– often with no dissent.

Votes on judicial nominations (January 2013-May 2014); graph by Sarah Binder; data from U.S. Senate.

Such purposeful partisanship– even on measures and nominations the GOP supports — adds new fuel to an ever escalating partisan fire fight in the Senate. Given the deep roots of what Steve Smith calls the Senate’s syndrome, November’s elections are unlikely to break the fever.