To be sure: I don't think the Ayers and ACORN attacks should be especially effective. I doubt they are especially effective. But poll numbers like this don't tell us one way or another. They're manufactured news designed to give the impression that lines of attack the MSM doesn't want to work aren't in fact working.
Just endorse someone, Mickey, and get it over with. Or not endorse, then half-endorse, or decide what others might think you would endorse and then half-bluff their bluff only to decide that you're for Obama if the Dems look like they might get more than 60 and then pull back if on Monday that may not look likely or decide later that the anti-anti-cool thing is to semi-half-retroactively endorse the half of the Dems you liked yesterday but can't bring yourself to support tomorrow. And hang in.