My hunch is that whatever points he scored off Warren were more than wiped away by a tone that Rep. Barney Frank, a Warren supporter, accurately described on Rachel Maddow’s show as “snarky.” In his effort to derail Warren in a debate, Brown may have undermined one of the most important aspects of his get-along-with-everybody brand.

The fact that he opened the encounter by dredging up a story that had been in hibernation since the spring about Warren’s claim of having some Cherokee background suggests that Brown is far less confident now than he had reason to be last summer, when he was running ahead in the polls. “Professor Warren claimed that she was a Native American, a person of color and as you can see, she’s not,” Brown said. In fact, many people in Oklahoma, where Warren grew up, have Cherokee blood. Warren told the story about her father and mother’s relationship to explain her belief that she is part Cherokee and parried by insisting that she had never used any claims of minority status to gain admission to university, or to get a job. Brown kept demanding that she release her personnel records to prove it. There was something strange, even offensive, about Brown’s making an assumption about Warren’s background on the basis of her skin color.

Brown also gave what I, at least, thought was an obnoxious answer when he began explaining his vote against the confirmation of Justice Elena Kagan, the former Dean of the Harvard Law School where Warren is a professor. After Warren criticized his vote, Brown said: “I’m sorry I didn’t vote for your boss.” It was an entirely unnecessary shot, and one I doubt was politically helpful.

Warren clearly had one central strategy in the debate: to remind Massachusetts voters of the votes Brown cast with the Republican minority in the Senate for various tax breaks for the wealthy and for corporate interests, including Big Oil, and more broadly to make the point that a vote for Brown is also a vote to put Republicans in charge of the Senate. She also kept reminding listeners that she supports President Obama, who is far ahead of Mitt Romney in Massachusetts.

Over and over, Brown kept referring to Warren as “Professor Warren,” on the theory that the middle class swing voters in Massachusetts don’t have much use for college professors. This is an old trick, used many years ago by former New York Senator James Buckley when he was challenged by Daniel Patrick Moynihan, a distinguished academic. When Buckley made his first “Professor Moynihan” reference in their first debate in 1976, Moynihan replied brightly: “Ah, now the mudslinging begins.”

It’s worth noting that Moynihan not only defeated Buckley, but also went on to become one of the Senate’s most distinguished members.