In recent weeks, as Mitt Romney has been practicing his debate “zingers” and the Obama campaign has been “managing expectations” by portraying the president as the lousiest debater since Admiral Stockdale, plenty of pundits—progressive ones, mostly—have been assuring us that the importance of debates is seriously overblown.

If Democrats weren’t already feeling blithely overconfident about President Obama’s re-election prospects, some are pointing to early voting as yet another source of sanguinity. The last time that there was a major “October surprise” in a presidential election, when Ronald Reagan “sealed the deal” against Jimmy Carter in a late-October debate, there was no such thing as early voting. Even absentee voting was in its infancy. But as part of progressive efforts to improve turnout, especially among low-income voters who sometimes can’t make it to the polls on Election Day, early voting has spread fast in recent elections—from 16 percent of all ballots cast in 2000 to about one-third of the total in 2008. This year, as many as 40 percent of Americans will vote early—which means they can, in the majority of states, already vote. And where does most early voting occur? In swing states. Iowa started voting yesterday. Ohio begins next week. As many as 70 percent of the votes in some crucial states—Colorado, North Carolina, Florida, Nevada—are expected to come from early birds.