One of the favorite statistics offered by political candidates is how often his or her opponent voted with The Person Voters Are Supposed to Hate. "My opponent voted with Barack Obama/Hillary Clinton/Ted Cruz/Vermin Supreme 98.4 percent of the time!" such ads say, causing the viewer to gasp and reconsider his vote. (That's a joke; voters fast-forward through political ads.)
The New York Times's Upshot blog articulated the various, relatively rare times that Hillary Clinton and Bernie Sanders disagreed during the years that their Senate careers overlapped. "Bernie Sanders voted with Hillary Clinton 92.5 percent of the time," Sanders's opponent might say, if his opponent didn't see voting with Clinton as a good thing.
It's easy to forget, though, that so many of the declared/likely 2016 candidates for the presidency used to serve in the Senate, each of them overlapping to some degree with some of the others. There's Clinton and Sanders on the Democratic side, along with Jim Webb of Virginia. And on the Republican side, Ted Cruz, Lindsey Graham, Rand Paul, Marco Rubio, Rick Santorum and Donald Trump. Ha ha ha. Can you imagine? No, but all the rest of them except Trump.
Using data from GovTrack.us, we pulled each senator's voting history while serving in that body. We calculated how often one senator voted Yea or Nay and compared it to each time that one of the other senators running for president in 2016 voted Yea or Nay. Then we tallied up the number of times the votes matched or didn't.
Unsurprisingly, members of the same party (counting Sanders as a Democrat here) voted together more frequently than members of opposite parties. The Democrats voted together an average of 89.3 percent of the time; the Republicans, 74.6 percent. No two senators voted together more often than Sanders and Clinton. No two senators voted together less often than Sanders and Cruz.
Cruz is one of the reasons that the Republicans' average is so much lower. But the real firebrand here is Rand Paul, who voted against the members of his party 15 percent of the time on average. (Cruz's average in voting against Republicans was 12.8.) Cruz and Paul disagreed with each other less than any other two Republicans.
If you're looking for those TV ad moments, there are some here. Opponents of Lindsey Graham can point out that he voted with Hillary Clinton more than a third of the time. And opponents of Rick Santorum? "Santorum voted with Hillary Clinton nearly 40 percent of the time when they served together.
Of course, Sanders can use that line, too.