The Demise of Senate Consensus

A month ago, Norman Ornstein and Thomas Mann sparked a debate with their WaPo column, "Let's Just Say It: The Republicans are the Problem." Personally, when I talk to reporters I try to be even-handed and to take the long view of history; surely Republicans have their complaints about Democratic behavior, and we can definitely go back in time and identify similar periods of high partisanship. 

Ornstein and Mann, however, correctly identify an anecdote that I found particularly revealing at the time: the January 2010 effort by Senate Republicans to defeat the debt commission that they had been calling for, with the swing votes coming from Republican cosponsors of the proposal. Returning to the theme of partisanship vs. polarization from yesterday, an ideologically extreme group of legislators will nonetheless jump at the chance to change policy when offered exactly what they are demanding. A partisan team, on the other hand, will vote against anything to keep the other side from getting a "win" and diluting their message.

Still, that's just one anecdote. Where's the evidence that there has been a major shift in legislative behavior? One measure used by legislative scholars is the size of winning coalitions on final passage votes. The size of these winning coalitions is a common measure of the degree of consensus on legislative decisions. Large coalitions suggest that, in the end, the members of the two parties come to an agreement on whether a bill should pass (most likely) or fail (unlikely). The process leading up to this decision may be contentious, and some controversial measures may be weeded out along the way, but large final passage margins suggests that some sort of consensus has developed. 

This figure displays the median coalition size on final passage votes from 1901 to 2010, including all bills, Senate resolutions, and joint resolutions except proposals that are statutorily protected against obstruction (trade agreements, budget resolutions, etc.).

From 1901 to 2006, there is an obvious trend toward increasing coalition size. In my book, I interpret this trend as evidence of the increasing influence of obstruction: senators are increasingly able and willing to filibuster bills that lack the support of a supermajority of the Senate, so bills pass by consensus or not at all. Over the last four years, however, the median coalition size has plummeted to levels not seen since the 1950s. Unlike the 1950s, however, this cannot be reasonably be interpreted as evidence that the majority party often succeeds without a filibuster. On the contrary, it is evidence that compared to the behavior of minority parties over the last four decades, the current minority party is extremely unlikely to arrive at a bipartisan compromise with the majority party. This forces the majority party to pass major measures without any support from the minority party (health care reform) or with a small number of Republican votes (2009 stimulus bill, banking reform). 

To be fair, Republicans will complain that their tactics are a response to attempts by Democratic leaders to limit their chance to debate measures openly. We shall return to this point in a later post. For now, I simply note that something systemic is going on in the Senate; consensus has become much more rare, and that makes it difficult to get work done in a chamber that functions on cooperation.