President Barack Obama and Republican candidate Mitt Romney discuss foreign policy in the third and final presidential debate.

UPDATED 11:30 p.m. ET -- President Barack Obama repeatedly ridiculed GOP presidential nominee Mitt Romney’s foreign policy views as dated and haphazard in his third and final debate with his Republican challenger, who in turn accused the president of diminishing American leadership during his first term.

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Obama took advantage of incumbency to remind voters throughout the 90-minute debate of his experience as commander-in-chief, and Romney’s lack thereof. The former Massachusetts governor, meanwhile, sought to project a deep familiarity with vexing global issues.

Slideshow: On the campaign trail Reuters, Getty Images In the final push in the 2012 presidential election, candidates Mitt Romney and Barack Obama make their last appeals to voters. Launch slideshow

The debate, held just 15 days before the election in the battleground state of Florida, veered at times from its stated emphasis on foreign policy and into issues of the economy and the budget – topics on which Romney holds an advantage over the president in most polls.

Rick Wilking / Reuters President Barack Obama (R) listens as Republican presidential nominee Mitt Romney (L) speaks during the final U.S. presidential debate in Boca Raton, Florida October 22, 2012.

But Obama sought to do to Romney with foreign policy – disqualify him in the eyes of voters – what his re-election campaign had tried to do on Romney’s economic proposals. The president openly mocked Romney’s suggestion, for instance, that Russia is the top geopolitical foe of the United States.

"You seem to want to import the foreign policy of the 1980s, just like the social policies of the 1950s and the economic policies of the 1920s," he said.

Andrea Mitchell and NBC's Truth Squad examine claims made by each candidate at the third and final debate of the 2012 presidential election in Boca, Raton, Fla.

Obama also derided Romney’s vow to grow the size of the Navy as indicative of the GOP nominee’s dated views toward national security.

"Governor, we also have fewer horses and bayonets, because the nature of our military's changed," Obama said. "We have these things called aircraft carriers, where planes land on them. We have these ships that go underwater, nuclear submarines. And so the question is not a game of Battleship."

The president says credibility is what’s important in dealing with world affairs.

Romney used his time at the debate to more broadly accuse Obama of presiding over a period of diminishing American leadership abroad.

“In nowhere in the world is America's influence greater than it was four years ago,” he said.

The former Massachusetts governor also voiced directly to the president an accusation – that Obama had apologized for American values – he has made throughout the campaign.

The president says a strong economy at home will strengthen the U.S. overseas during the third and final presidential debate of 2012.

“You said that on occasion America had dictated to other nations,” Romney said. “Mr. President, America has not dictated to other nations. We have freed other nations from dictators.”

That attack prompted Obama to respond with a blistering characterization of Romney’s own trip to the United Kingdom, Israel and Poland this past summer.

“When I was a candidate for office, the first trip I took was to visit our troops. And when I went to Israel as a candidate, I didn't take donors. I didn't attend fundraisers,” Obama said in reference to a fundraiser Romney held while in Jerusalem this summer. “I went to Yad Vashem, the Holocaust museum there, to remind myself the nature of evil and why our bond with Israel will be unbreakable.”

Obama’s tough rhetoric, though, betrayed his campaign’s outward confidence amid a series of national and battleground state polls suggesting the election had tightened to a dead heat over the past month, since Romney’s strong performance in their first debate on Oct. 3. Republicans argued that the president’s posture was that of a candidate who has fallen behind Romney over the past few weeks.

Romney used a number of opportunities to steer the debate back toward domestic issues, on which the former Massachusetts governor has mostly staked his campaign. Romney got an opportunity to recount his five-point economic plan, and his direct-to-camera closing statement emphasized the economy as much as foreign policy.

The Republican nominee also largely declined to make as sharp of a case about Obama’s handling of the Sept. 11, 2012 attack on a U.S. diplomatic mission in Benghazi, Libya, which resulted in the deaths of four Americans, including U.S. Ambassador Christopher Stevens. Romney has used the administration’s response to that incident to make up ground versus Obama, but scarcely dwelled on Libya – the opening topic of Monday evening’s debate.

The Republican presidential nominee says America must take a leading role in promoting U.S. values during the third presidential debate of 2012.

Romney also tried to dissociate himself with Republican hawkishness, refusing to engage a hypothetical question about Iran’s nuclear program, ruling out a military strike against Libya and stating the U.S. “can't kill our way out of this mess” as it relates to al Qaeda.

The debate’s tangents offered Obama other opportunities to go after Romney. The upcoming “sequester” – the automatic spending cuts, particularly to the defense budget, set to take effect at the beginning next year – prompted the two candidates to renew their squabbling over Romney’s tax plan.

And Obama – whose decision to extend federal aid to Detroit’s troubled automakers in 2009 has become a pillar of his pitch to voters in Midwestern battleground states – eagerly pounced on a tangent involving the auto industry to criticize Romney.

The Republican nominee also largely shrugged off Obama’s attacks as obfuscatory.

"Attacking me is not an agenda," Romney said early at the debate, at Lynn University in Boca Raton, Fla.

Whether Monday’s debate would provoke a thinning sliver of undecided voters to make a decision was another question, to which the answer wasn’t immediately clear following the debate.

Both Obama and Romney had arranged major rallies with their running mates on Tuesday so as to project momentum in the closing two weeks of the campaign. Both campaigns left Boca Raton with a self-professed sense of confidence, validation or dismissal of which will come on Nov. 6.