DENVER — The first presidential debate is already two-thirds over, and President Barack Obama is struggling to go up against a surprisingly strong performance from his Republican challenger Mitt Romney.

Obama did manage to land the first — and only — "zinger" of the night, early on, during a heated sparring match over Romney's tax plan.

After slamming Romney for wanting to cut taxes on the country's highest income earners, Romney argued that that those earning more than $200,000 actually wouldn't see a tax break because his plan would eliminate those deductions and loopholes that benefit the rich.

"For 18 months he's been running on this tax plan," Obama interjected. "Now five weeks before the election, he's saying his big, bold idea is 'nevermind.'"

"He's been asked over a hundred times which deductions and loopholes he would eliminate," he added later. "He can't identify them."

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