COLUMBUS - President Obama says he is entirely confident that a sufficient number of Americans back his bid for a second term, but that motivating those voters to show up at polling places Tuesday remains a challenge that could determine the election's outcome.

"We have enough voters to win, it's just a matter of whether they show up," Obama told syndicated radio talk show host Warren Ballentine in a taped interview that ran this morning.

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"Obviously there are going to be some voters who at this late date may still be undecided, and if they are, I am making a closing argument," he said. "But the main thing I want everybody to understand is that the number of undecided voters at this point is much smaller than the number of voters who support me but just aren't voting.

"If all the people who support me vote, then we'll be fine," he said.

Obama acknowledged that the race would likely go down to the wire, with enthusiasm levels among the competing parties' supporters playing a potentially decisive role.

"For folks who are listening who are sporadic voters, occasional voters, who say to themselves, 'I prefer Obama but I'm busy,' this is not the time to sit and do nothing," he said. "This is the time to make sure your voices are heard so I can be fighting for you in Washington the next four years."

Listen to the entire interview HERE .