The Parties Really Are Unified

A while back, I took Gail Collins to task for characterizing Senate Democrats as “rabid guinea pigs in a thunder storm,” with the presumption that it would be hard for Democratic majorities to maintain discipline within their ranks. I pointed out that party unity has been increasing over time, that Democrats are lately more unified than Republicans, and that, in general, party unity is the rule, not the exception.

On Monday, CQ released its party unity scores for the 111th Congress, and—guess what?—the parties were really, really unified. Despite the size of the Democratic House and Senate majorities. Despite the influx of Blue Dogs. Despite the influx of rabid guinea pigs, or whatever. Indeed, Senate Democrats, Collins’ example, were the most unified they have been since 1956. Here is the CQ graph:


Here is a graph I made from the 1991-2010 data at the Washington Post’s U.S. Congress Votes Database. They calculate party unity a bit differently but the same basic story emerges: high levels of loyalty, generally increasing over time.


If you want to see the data since 1879, thanks to Nolan McCarty, Keith Poole, and Howard Rosenthal, scroll down to the bottom of the Polarized America page.

Narratives of declining party power and party unity are apparently quite appealing. Journalists love to seize on every instance of disloyalty and dissension. Here’s the story on Ben Nelson, for example. By contrast, a legislature where members’ votes are pretty predictable isn’t such an exciting story. But that’s the legislature we have.

4 Responses to The Parties Really Are Unified

  1. FreeDem January 5, 2011 at 11:53 pm #

    Isn’t there selection bias in the party unity scores for the Senate? Because of the threat of the filibuster, Reid wouldn’t move most bills to the floor without the assurance that he has a high degree of party unity. The more moderate members would hold out, initially, until concessions were made. The higher unity score isn’t just a product of Democratic cohesion, but the impact of increased use of the filibuster by Republicans.

  2. marc sobel January 7, 2011 at 12:38 am #

    I assume that these are based on voting history but I suspect it does not capture the way the Senate Dems for example keep on capitulating until they come up with enough votes.

    Certainly there were Democrats who kept the health care bill weak.

    If we don’t stand for anything then party unification is a moot point.

  3. Austin January 10, 2011 at 4:14 pm #

    Huh. This graph seems to show that when a party is in control of a house, it’s more disciplined than the minority. Makes sense.


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