Ron Paul is surging in Iowa,  and sensing a threat, his opponents are on the attack, firing missiles at what they say are the Texas congressman's weaknesses.

"Ron Paul thinks it would be fine if the Iranians obtained nuclear weapons," presidential candidate Rep. Michele Bachmann, R-Minn., said at a campaign stop in the Hawkeye state.

"You don't have to vote for a candidate who will allow Iran to have a nuclear weapon to wipe Israel off the face of the earth," echoed Texas Gov. Rick Perry.

"One of the people running for president thinks it's okay for Iran to have a nuclear weapon. I don't," said former Massachusetts governor Mitt Romney, a clear swipe at Paul's hands-off approach to foreign policy. "I don't trust the ayatollahs, I don't trust Ahmadinejad," Romney added referring to Iranian President Mahmoud Ahmadinejad.

The latest NBC News/Marist poll shows Paul and Romney are neck and neck in Iowa. Romney has a slight lead of two  points, but with a margin of error of 1.8 percent in the survey the two candidates are in a virtual tie.

Paul has not responded to the attacks, and he stands by his hands-off approach to foreign policy. At a campaign event in Perry, Iowa, he told supporters that western sanctions against Iran are "acts of war" that are likely to lead to an actual war.

Speaking on the showdown over the Strait of Hormuz, Paul said Iran would be justified in responding to sanctions by blocking the crucial waterway, and emphasized that the United States should not get involved.

"I think the solution is to do a lot less a lot sooner, and mind our own business, and we wouldn't have this threat of another war," Paul said.

Paul's foreign policy views are out of step with past Republican presidential campaigns, which have typically supported United States military intervention in troubled spots overseas. A smaller American footprint abroad, say rivals, would be bad for the country.

"Ron Paul would be dangerous as president of the United States," said Bachmann.

Former speaker of the House and fellow presidential candidate Newt Gingrich told CNN he would not vote for Ron Paul if he were the nominee. Former Pennsylvania senator Rick Santorum, who is in third place behind Paul in this week's CNN/Time/ORC and NBC/Marist polls, said Paul would be the "least likely" candidate to win against President Obama.

Even former Utah governor Jon Huntsman is getting in on the Paul pile-on. Huntsman, who is skipping the Iowa caucus, told voters in New Hampshire that voting for Paul would ultimately be futile.

"He's not electable at the end of the day. Let's be real about it," Huntsman said.