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President Obama is admitting what most of the country already had concluded about the first presidential debate: "I had a bad night."

Obama, trying to bounce back after his lackluster performance last week in the debate against Mitt Romney, doubled down Wednesday on his campaign's attempt to suggest Romney won that face-off partly because he wasn't being upfront about his policy positions.

"Governor Romney had a good night. I had a bad night," Obama said in an interview with ABC News. "The fundamentals haven't changed. Governor Romney went to a lot of trouble to hide what his positions are."

Obama said he plans to do more at the next debate to convey "how much is at stake and how deeply I care about it," and he had words of advice for his vice president, Joe Biden, who is preparing for his own debate Thursday against Paul Ryan.

"Joe just needs to be Joe," Obama said. "Congressman Ryan is a smart effective speaker, but his ideas are the wrong ones."

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The interview occurred on a day when a post-debate Fox News poll shows Romney erasing Obama's advantage in the national head-to-head matchup. Various battleground state polls still show Obama with an edge, but Romney has started to close the gap in many of those states.

A SurveyUSA poll commissioned by the Las Vegas Review-Journal and 8NewsNow showed Obama leading by only 1 percentage point in Nevada.

Another survey in New Hampshire showed Romney closing a 15-point deficit and pulling within 6 points of Obama. The WMUR Granite State Poll still showed Obama in the lead, but it marked a significant gain for Romney over the course of just one week.

A rapid-fire succession of state and national polls showed a similar trend.

In a national Gallup poll released Tuesday, Romney was leading 49-47 percent among likely voters. A Reuters-Ipsos national poll showed the candidates tied. The latest Fox News poll, released Wednesday, showed Romney with 47 percent to Obama's 46 percent.

The RealClearPolitics average of polling now shows Romney leading by less than 1 percentage point in Florida, and Obama leading by the same airtight margin in Ohio. Obama was well ahead in those states just days ago.

Further, Romney's post-debate surge appears to have all but wiped out Obama's once double-digit lead among women voters.

A Pew Research Center survey released Monday depicted a remarkable swing in the numbers, with Romney pulling even among women in polling late last week. In September, the same polling outfit showed Obama leading by 18 points among women.

Among all likely voters surveyed, Romney climbed from an 8-point deficit last month to a 4-point lead.

There's little question that his debate performance has played a role. A separate Gallup survey showed registered voters deemed Romney the winner by 72-20 percent, marking the biggest debate victory in Gallup's recorded history.

But Obama said Wednesday he wasn't about to throw in the towel.

"This was one event. We've got four weeks to go. Nobody is going to be fighting harder than I am," Obama told ABC News before getting in a plug for the next presidential debate. "What they need is to make sure they tun in on Tuesday next week."