Feingold has an advantage that some endangered Democrats are lacking: He's genuinely adored by his base. The idea that he could lose is not just shocking but also cosmically unfair. Eighteen years working on campaign finance reform and the Supreme Court unspools his legislation? A lifetime of public service that's kept him poor, and he's being out-man-of-the-peopled by a wealthy industrialist? It doesn't matter that Democrats are actually withstanding the "secret money" onslaught with money of their own—it just doesn't seem fair.
I would add that Feingold, the only Senator to vote against the Patriot Act and a consistent critic of the Bush and Obama administrations on civil liberties and executive power, is being swept out by a movement that is not only pro-torture and war, but also has the temerity to assume a posture of outrage about government overreach.
It's got the ludicrous tragedy of a Tom Stoppard play.