President Barack Obama takes his Republican opponent Mitt Romney to task over foreign policy in the final presidential debate before November’s election.
The incumbent president said the former Massachusetts governor had been “all over the map” in his positions on major foreign policy issues.
“Every time you have offered an opinion you have been wrong,” he said.
“You said we should have gone into Iraq, despite the fact there were no weapons of mass destruction. You said we should still have troops in Iraq to this day. You said we shouldn’t be passing nuclear treaties with Russia.”
“I congratulate him on taking out Osama bin Laden and going after the leadership of al-Qaeda, but we can’t kill our way out of this mess,” he said.
Mr Romney said Mr Obama had sent out the wrong message by embarking on an “apology tour” of the Middle East during which he said the US had at times dictated to other nations, a charge dismissed by the president as a “big whopper”.
The Republican challenger also said he would take a tougher line on Iran, singling out the country’s controversial nuclear programme as the greatest threat to US security.
“I think from the very beginning, one of the challenges we’ve had with Iran is that they have looked at this administration and felt that the administration was not as strong as it needed to be,” he said.
“We’re four years closer to a nuclear Iran and we should not have wasted these four years.”
Mr Obama committed to stand with Israel against threats from Iran or any other nation, but said terrorist networks were the principal concern for national security.
He highlighted his administration’s change of focus of attention to “those who actually killed us on 9/11”, saying that under this strategy “al-Qaeda’s core leadership has been decimated”.
The president also dismissed claims he had run down the armed forces to levels not seen since the early 20th century.
“You mentioned the navy, for example, and that we have fewer ships than we did in 1916. Well, governor, we also have fewer horses and bayonets because the nature of our military’s changed,” he said to laughter from the audience.
The heated debate at Lynn University in Boca Raton, Florida repeatedly strayed into domestic policy, with Mr Romney arguing that national security depends on a strong economy.
Going into the debate the candidates were neck and neck after the Romney campaign was boosted by good performances in the first two clashes.
A poll taken by broadcaster CBS immediately afterwards suggested voters thought Mr Obama had performed best in Boca Raton, by 53 per cent to 23 per cent.
Both men will now embark on two weeks of whirlwind campaigning.
Billed by the campaign as a two-day, non-stop “America Forward tour”, Obama is scheduled to travel through Ohio, Florida, Virginia, Iowa, Colorado and Nevada.
He will also make a detour on Wednesday to California, which is considered safely in his column, for an appearance on NBC’s The Tonight Show with Jay Leno.
Romney prepared extensively for the foreign policy debate, coming off the campaign trail on Saturday for three days of preparation at a waterfront hotel in Florida.
His top political and policy advisers were with him, as was Senator Rob Portman of Ohio, who played Obama in the mock debates and has become an increasingly influential adviser to the nominee.
On Tuesday, Romney heads west to reunite with vice-presidential hopeful Paul Ryan, staging joint rallies in Nevada and Colorado, and from there, Romney campaigns in Iowa and Ohio.
Advisers said Romney would start delivering his closing argument to voters this week, and he is considering making a major speech on debt and government spending in the coming days.