The Senate on Tuesday could not overcome a Democratic filibuster on a measure to approve construction of the Keystone XL pipeline. The vote mostly fell along easily recognizable lines. Every Republican voted for cloture, as did 14 relatively conservative Democrats. There were five more surprising votes: those of Democratic Sens. Michael Bennet of Colorado, Bob Casey of Pennsylvania, Tim Johnson of South Dakota, Bill Nelson of Florida and independent Sen. Angus King of Maine.
When we build a simple logit model to predict the Keystone vote — taking into account the ideology of each senator (as measured by DW-Nominate) and partisan lean of each state (as measured by the 2012 presidential vote) — it correctly calls the votes of 95 senators. The model is a very good fit. The five senators mentioned at the top are the ones who are misclassified. The model projects Johnson, King and Nelson to vote yes; they voted no. The model expects Bennet and Casey to vote no, and they voted yes.
There’s a fairly clear explanation for Johnson, King and Nelson. None of them has an election to worry about for at least another four years, so electoral repercussions aren’t really an issue. All three also received at least an 85 percent score from the League of Conservation Voters (LCV), an environmental advocacy group, in 2013. The average Democrat who voted yes scored a 76 percent. Opponents of the pipeline have argued that the potential benefits are outweighed by the negative environmental impact.
Bennet and Casey may believe the pipeline will keep gas prices down and create jobs — maybe they believe so more than the average Democrat. But a cynic might say their yes votes were about winning elections.
The Pew Research Center found that the Keystone Pipeline is supported by 59 percent of Americans, and Colorado and Pennsylvania have elected Republican senators in the last five years. Bennet is up for re-election in two years, and he just saw his Democratic colleague Mark Udall go down in Colorado. Bennet voted for the pipeline, despite earning a 92 percent from the LCV in 2013. (Bennet had previously been against the pipeline in 2012, though he voted for it in 2013.)
Casey isn’t up for re-election until 2018, but he first supported the pipeline in his re-election year of 2012. His yes vote is at odds with his LCV score of 85 percent.
Ultimately, we can’t know for sure who voted Tuesday for policy reasons, who voted for electoral reasons and who had both in mind — with one possible exception. Sen. Mary Landrieu of Louisiana, who faces a runoff election against Republican Bill Cassidy on Dec. 6, desperately wanted to pass the bill to help her re-election chances. She didn’t get her wish, but it probably wouldn’t have mattered. Landrieu, as I’ve previously discussed, was a heavy underdog no matter what happened in the Keystone vote.