I know everyone's still preoccupied with Obama's "bitter" comments, but I'd argue that something he said yesterday is much, much worse:
We've seen just a skyrocketing autism rate. Some people are suspicious that it's connected to the vaccines. This person included. The science right now is inconclusive, but we have to research it.
Actually, as the WaPo's Michael Dobbs points out, the science isn't inconclusive: numerous studies have found no link between vaccines and autism. But there are plenty of people who don't let the science get in the way of their suspicions. Having two out of the three presidential remaining presidential candidates fan those suspicions--McCain has made comments similar to Obama's--doesn't help matters.
P.S. Which is all the more reason to get behind this ScienceDebate2008 idea.