It goes like this. Sen. John Kerry (D-Mass.), the RNC reminds us (three times!) once said that he voted for $87 billion in Iraq War funding before he voted against it. This, says the RNC, is exactly what Sen. Ben Nelson (D-Neb.) would be doing if he failed to join a Republican filibuster of health care reform and instead voted to move the bill to the floor–where everyone expects him to vote against it.

One problem with this is that it’s not technically true. In 2003, Kerry voted for a bill that would have appropriated the $87 billion in funding for Iraq while repealing some Bush tax cuts. He voted against the final bill which didn’t repeal the tax cuts. In this case, the GOP is defining “moving a bill to the floor” as “supporting it.” If that’s flip-flopping, then every Republican member of the Senate has flip-flopped–they allow bills to go to the floor, then vote against them, all the time.

Again, this is largely an academic discussion, as this video won’t be widely viewed outside a base of political junkies and partisan activists. But it demonstrates real progress for this myth of the Senate as a supermajority-driven institution, instead of one where the filibuster has been wildly, flagrantly abused beyond all recogniition.

“I plan to support her,” Nelson told a reporter for the Lincoln Journal Star.

Nelson said he was influenced by Sotomayor’s endorsement from the American Bar Association and her extensive experience as a judge. He added that “the record shows she is not an activist,” she would not bring her “personal bias or an agenda” to the Supreme Court, and  she has “a great respect for the law.”

The Senate is expected to vote on the nomination Wednesday.

Intrigued, I called the study’s head researcher, Douglas Oxley of the University of Nebraska, to see if he agreed with this conclusion.

“In some ways [the study has] been misinterpreted,” said Oxley. He said that his study didn’t find a link between DNA and political leanings. “We could have things happen to us in the womb or later in life that could cause” physiological and ideological differences.

The study, released yesterday, tested the physiological responses of 46 participants to various threatening images, like bloody faces. It found that people who self-identified as “in favor of socially protective policies” responded much more strongly to the stimuli than people who held more liberal views on such issues as welfare, abortion, immigration, gay rights and school prayer.

The researchers concluded that people of different ideological persuasions have divergent physiological reactions, and that people with socially conservative views tend to be more shocked by potentially threatening stimuli.

“Some people have said that we’re calling conservatives ‘frightened’ or something along those lines,” Oxley said. “And we’re not. All we’re suggesting is that there’s a physiological difference between people who hold one set of political beliefs and people who hold another set of political beliefs.”

The study had its limitations — the sample size was small and all of the subjects were white Nebraskans — but it’s still a small step toward a greater understanding our ever-increasing ideological divide, even if the answer doesn’t lie in our genes.