Even so, the political opponents were less at odds than in the previous two debates, taking similar positions on courses of action for some world affairs.
Obama highlighted Romney's inexperience, ridiculing Romney for expressing Cold War-era concerns about Russia being America's biggest geopolitical foe, while Romney did his best to portray himself as an alternative commander-in-chief with a solid grasp on world affairs.
"The 1980s are now calling and asking for their foreign policy back," the president told Romney at one point.
Both candidates, whom pollsters have locked in a virtual dead heat, concurred on issues, including the president's approval of the use of drone strikes to kill suspected militants, a commitment to Israel, and how to deal with Iran's nuclear ambitions and Syria's civil war.
Romney even prefaced one of his first jabs at Obama by congratulating the president for making the order to kill al-Qaeda mastermind Osama bin Laden.
The two candidates sat for an exchange moderated by CBS newsman Bob Schieffer in Boca Raton, Fla., with the first opportunity to answer a question — concerning tensions in the Middle East and Libya — going to Romney.
"What we're seeing is a pretty dramatic reversal of hopes for that region," Romney said. "But we can't kill our way out of this mess. We're going to have to put in place a very comprehensive strategy to help the world of Islam … reject this radical violent extremism."
The former Massachusetts governor, trying to portray himself as more presidential, was expected to hammer the president hard on the Libya question, which has been seen as a political vulnerability for the Obama camp. But he didn't pursue that line as aggressively as he was expected to, noted CBC's Evan Soloman in a post-debate analysis.
The Sept. 11 attack on the U.S. Consulate in Benghazi killed American envoy to Libya Chris Stevens, as well as three other Americans.
Obama, appearing comfortable with his foreign policy experience, was quick to defend his record on the Middle East over the last four years.
"We ended the war in Iraq, refocused our attention on those who actually killed us on 9/11, and as a consequence al-Qaeda's core leadership has been decimated," he said.
With respect to Libya, Obama said that when the White House was alerted about the deadly situation at the consulate in Benghazi, "we did everything we could to secure those Americans that were still in harm's way."
He added that his second pledge was to investigate what happened, "and No. 3, most importantly, that we would go after those who killed Americans and we would bring them to justice. And that's exactly what we're going to do."
Regarding international trade and the threat of China's giant economy, Romney said China can be a partner, but "that doesn't mean they can roll all over us and steal our jobs on an unfair basis," referencing reports of foreign hacking and alleged intellectual property theft at the hands of the Chinese.
Obama said that since he came into office, U.S. exports have doubled to China, "and currencies are at their most advantageous point for U.S. exporters since 1993."
"We believe China can be a partner, but we're also sending a very clear signal that America is a Pacific power, that we are going to have a presence there," he said. "We are working with countries in the region to make sure, for example, that ships can pass through, that commerce continues, and we're organizing trade relations with countries other than China so that China feels more pressure about meeting basic international standards."
'A game of Battleship'
Monday night's contest saw what appeared to be a more moderate Romney, who spoke of diplomatic solutions to the crisis in Syria and punishing Iran with tighter economic sanctions.
There were also moments when the president tried to portray his Republican opponent as out of touch.
- Obama's 'horses and bayonets' quip trends after debate
While Romney cast himself as a leader who would pour more resources into bolstering the U.S. military, he accused the president of neglecting to back the armed forces with more funding, and drew comparisons with naval fleets from the First World War to make his point.
"Our military is smaller than any time since 1917, and the Navy needed 313 ships, and we're at 285, and we're headed to the low 200s," he said. "That's not acceptable for us, and our air force is older and smaller than any time since it was founded in 1947."
Obama seized on the moment, remarking that Romney was simplifying numbers and treating national security resources like "a game of Battleship."
"You said that we have fewer ships than in 1917. Well, governor, we also have fewer horses and bayonets because the nature of our military has changed," Obama countered. "We have these things called aircraft carriers, where planes land on them and we have ships that go underwater — nuclear submarines."
The Obama retort quickly went viral on Twitter, with bloggers using the hashtag #horsesandbayonets.
Sparring over Syria response
On the subject of the civil war in Syria, Obama said the U.S. should "do everything we can to help the opposition," though the response to what he called a "heartbreaking" scenario should be a measured one.
"Anything more we do to get entangled in Syria is a serious step," Obama said.
"But what we can't do is to simply suggest — as Gov. Romney has at times suggested — that giving heavy weapons for example to the opposition is a simple proposition that would lead us to be safer over the long term."
Romney said the removal of Syrian dictator Bashar al-Assad is a high priority, and agreed the U.S. must not get drawn into a military conflict.
He suggested organizing responsible parties and then trying to arm those opposition groups to defend themselves against the Assad regime.
"We do need to make sure that they don't have arms that can get into the wrong hands," he added.
Both candidates claimed Israel as a great ally in the Middle East, when asked whether they would make a proclamation that a nuclear strike against Israel by Iran would be tantamount to attacking the U.S.
Obama boasted that America's diplomatic approach against Iran over its nuclear program, including "crippling" economic sanctions, has been effective in punishing the Islamic republic, with oil production having plunged to its lowest levels in 20 years and the economy "in a shambles."
47% favour Obama for 'wise' foreign policy
Romney echoed the president's sentiments, but rejected Obama's suggestion that he was pushing for America to take a more hawkish approach with Iran.
"I want to underscore the same point the president made, which is if I'm the president of the United States — when I'm president of the United States — we will stand with Israel. And if Israel is attacked, we will have their back," he said.
Romney said it's essential to understand that America's mission is to dissuade Iran from acquiring nuclear weapons.
"Of course a military action is the last resort — it is something somebody would only, only consider if all of the other avenues had been tried to their full extent."
As CBC News reporter Keith Boag noted, it seemed Romney was determined not to make political errors at this stage in the game.
"[Romney] has been so agreeable that he hasn't defined any important difference on foreign policy," Boag wrote on Twitter. "This makes sense, given that he has used the debates to essentially tie the race, and why mess thing up with two weeks to go when [get out the vote] is now the name of the game."
The two presidential candidates were aiming for a commanding performance to settle the seesaw dynamics of the first two debates: Romney gave Obama an old-fashioned shellacking in the first round, and the chastened president rebounded in their second encounter.
The 90-minute faceoff at Lynn University offered the candidates their last opportunity to stand one-on-one before tens of millions of Americans and command their undivided attention before next month's election.
When it comes to their foreign policy credentials, both candidates have reasons for optimism and concern: While foreign policy has been an Obama strength throughout the campaign, some recent polls show his advantage narrowing. The Pew Research Center's October poll, for example, found that 47 per cent of Americans favoured Obama to make "wise decisions about foreign policy," while 43 per cent preferred Romney.