President Obama aggressively questioned Mitt Romney's foreign policy credentials during the final presidential debate Monday while the Republican calmly countered that the president's failed economy had made America more vulnerable.

Throughout the 90-minute discussion in Boca Raton, Fla., Romney sought to dispel the notion that he was a war hawk in the mold of President George W. Bush, instead attempting to present himself as a poised potential commander in chief. In contrast, Obama looked to flex presidential muscle and minimize the types of national-security doubts that voters typically have about Democrats.

"Every time you've offered an opinion you've been wrong," Obama told Romney, accusing the Republican of being "all over the map" on issues ranging from the wars in Iraq and Afghanistan to how he would handle the uprisings in the Arab Spring.

To which Romney replied, "Attacking me is not an agenda."

At the end of their final face-to-face encounter, neither side had a clear claim to victory. For the Republican, the night was about showing compentency and steadiness. In doing so, Romney passed on an opportunity to hit Obama over his handling of the terrorist attacks at the U.S. Consulate in Libya, an area many analysts said was Obama's greatest foreign policy vulnerability.

Instead, Romney appeared to recognize America's weariness with more than a decade of war in Iraq and Afghanistan. "We can't kill our way out of this mess," he said while crediting Obama for the killing of Osama bin Laden. At another point, the former Massachusetts governor said, "We don't want another Iraq. We don't want another Afghanistan."

Obama pushed hard to convince viewers that Romney was not up to the task of taking on the wide range of global challenges that come with the presidency.

"A few months ago you said the greatest geopolitical threat was Russia," Obama said. "The 1980s are calling and asking for its foreign policy back."

Later in the evening, the president mocked Romney for lamenting the demise of the Navy.

"The question is not a game of Battleship," Obama said. "Yes, we have fewer ships than we had in 1916. We also have fewer horses and bayonets."

While the discussion was aimed at foreign affairs, on several occasions Romney deftly steered it back to what he called Obama's failed economic policies.

He called the soaring federal deficit the nation's "biggest national security threat." And he argued that Obama's mishandling of the economy had weakened American standing on the global stage.

"The president hasn't balanced the budget yet," Romney said. "I expect to have the opportunity to do so myself."

The presidential contenders also traded jabs over the auto bailout, with Obama repeatedly insisting that Romney would have shut down the auto industry. In the most heated exchange of the night, both men insisted their point of view was supported by the record. Romney alluded to an opinion piece he wrote for the New York Times in 2008 in which he said, "it is not wrong to ask for government help, but the auto makers should come up with a win-win proposition." Both men pushed hard on the issue, a crucial one in the battleground state of Ohio, where many feel the election will be decided.

When asked the greatest threat facing the United States, Obama answered terrorism from groups like al Qaeda. Romney said a nuclear-armed Iran was America's greatest threat. And he argued the government in Tehran was "four years closer" to having the bomb. Obama insisted that U.S.-imposed sanctions were taking a toll on Iran and dismissed reports that his administration had agreed to one-on-one negotiations with the government there.