This off the cuff Atlantic liveblog post offers the most trenchant analysis of the Ayers/ACORN attacks I've read yet:
You just heard why John McCain will lose. He pivoted from an attack on ACORN and Ayers to his campaign getting the economy back on track. Worst segue ever. The two don't line up. Ayers and ACORN don't take you to a larger campaign theme. This isn't "Swiftboating" which took you to the War on Terror. This isn't Willie Horton, which took you to crime. This isn't "States Rights" which takes you to busing and the Voting Rights Act. It's just empty demagoguery. It doesn't say anything about what is foremost in the electorate's minds.