Two paradoxical findings from a new Washington Post-ABC News poll offer unique insight into how Obama's chances at re-election hinge closely on his ability to inspire supporters to get out and vote.

1. Obama voters are 10 percentage points more likely than Romney voters to say they are "very enthusiastic" about supporting him 56 percent to 46 percent.
2. Romney voters are seven points more apt than Obama voters to say they are "absolutely certain" to vote in November.

The reason for these apparently contradictory findings is that while Obama's most fired up supporters are absolutely certain they will show up on Election Day, his less enthusiastic supporters are not, to borrow an Obama campaign slogan, "ready to go!"

In the Post-ABC poll, fully 93 percent of Obama's "very enthusiastic" voters say they are a lock to vote in November, but that drops 24 percentage points (to 69 percent) among those who are "somewhat enthusiastic" or even less jazzed. That's more than double the 2008 gap between enthusiastic and less enthusiastic Obama supporters -- 10 percentage points in a Post-ABC poll at this point four years ago -- and is a double whammy since fewer Obama supporters are "very enthusiastic" this time around.

By contrast, fully 84 percent of "somewhat" or less enthusiastic Romney voters nevertheless say they are absolutely certain to show up and vote. The difference in vote likelihood among less enthusiastic supporters for each candidate was not apparent in a late August Post-ABC poll, before the party conventions. Additional polls this fall will help determine the durability of this dynamic.

There's a silver lining for Obama: enthusiasm among his supporters is on the rise after the two conventions, with 56 percent of his voters now "very enthusiastic" about him, compared with 48 percent in late August. That trend could continue as his wayward supporters focus in on the battle between Obama and Romney.