Ben Smith points to a poll that reveals more than half of Democrats either believe it "very likely" or "somewhat likely" that George Bush knew about 9/11 in advance - or actually was in on the plot.

There aren't a lot of great public numbers on the partisan breakdown of adherents to that conspiracy theory, but the University of Ohio yesterday shared with us the crosstabs of a 2006 poll they did with Scripps Howard that's useful in that regard.

"How likely is it that people in the federal government either assisted in the 9/11 attacks or took no action to stop the attacks because they wanted the United States to go to war in the Middle East?" the poll asked.

A full 22.6% of Democrats said it was "very likely." Another 28.2% called it "somewhat likely."

That is: More than half of Democrats, according to a neutral survey, said they believed Bush was complicit in the 9/11 terror attacks.

I'm still not sure this represents actual belief, as opposed to a kind of trash talk about a president you hate. (Bush wasn't mentioned in that survey question, but had been earlier in the poll.)

It does, though, offer a bit of context to the suggestions on the left that mass insanity has beset the GOP.