Forecasting climate votes in the Senate

Nate Silver, the statistician who gained prominence in the last election cycle with his predictions for the presidential race, has modeled the prospects of the Waxman-Markey climate bill in the Senate. The analysis is necessarily based on a number of assumptions, such as that the bill doesn’t change in its progress to the Senate floor. So its an artificial exercise, but an interesting one.

Silver’s model finds 51 votes with a reasonably high probability (75% or higher) of voting in favor of the bill (that’s not how Silver divides up the probabilities, but there’s a clear split in his model between Mark Begich of Alaska (77.98%) and the next highest Senator, Olympia Snowe of Maine (55.13%)). That would be barely enough to pass the bill, but not nearly enough to break a threatened filibuster. Silver sees 9 problematic votes in the Democratic caucus and only 2 Republicans (Snowe and Collins of Maine) with a double-digit probability of breaking ranks with their party.

Silver’s conclusion:

Overall, this is a slightly better assessment than I expected. Although the model considers only 52  Senators to be more likely than not to vote for the bill, there are somewhere between 62-66 votes that are perhaps potentially in play. But . . . further compromises would almost certainly be needed, some of them designed to placate as few as one senator. The question is how many ornaments the Democrats could place on the Christmas Tree before it starts to collapse under its own weight.

Nate Silver, US Senate, Waxman-Markey