DES MOINES, Iowa - Mike Huckabee called Mitt Romney a dishonest politician who couldn't be trusted with the presidency, turning up the heat Sunday in a close-and-getting-closer Republican race in Iowa.

Romney's camp accused hard-charging Huckabee of 'testiness and irritability,' a description that could apply to almost any candidate in the tumultuous Iowa showdown.

As six candidates took their closing messages to morning talk shows, Democrat Barack Obama acknowledged that the criticism directed at him might be taking a toll.

'That may have some effect but ultimately I'm putting my faith in the people of Iowa that they want something better,' Obama said on NBC's 'Meet the Press.'

Headed into the final days of the closest caucuses in a lifetime, public and private polls showed that Obama, Sen. Hillary Clinton of New York and former North Carolina Sen. John Edwards were locked in a three-way tie for the lead. A new poll of the Republican race suggested that Huckabee's surprise surge might have stalled; his lead over Romney evaporated.

Huckabee said he might have been hurt by Romney ads and mailings criticizing his record as governor of Arkansas. Lacking Romney's resources, Huckabee used an appearance on the NBC show to accuse Romney of distorting his own public record.

'If you aren't being honest in obtaining the job, can we trust you if you get the job?' Huckabee asked.

He accused Romney of running 'a very desperate and, frankly, a dishonest campaign' against himself and rival John McCain.

Calling the former Vietnam POW a hero, Huckabee said, 'I felt like when Mitt Romney went after the integrity of John McCain, he stepped over the line.'

Romney spokesman Kevin Madden said Huckabee can't defend raising taxes and granting clemencies to murderers in Arkansas.

'It's a record that is tough to defend, so his testiness and irritability when being questioned about it is obvious,' Madden said. 'But, Mike Huckabee's lashing out with personal attacks against Governor Romney that have no merit or substance is quite unfortunate. Campaigns should be about the issues.'

Romney is fighting on two fronts, hoping to defeat Huckabee in Iowa and McCain in New Hampshire to vault himself to the nomination.

McCain said on ABC's 'This Week' that Romney's criticism of him and Huckabee 'shows they're worried.'

But McCain, asked whether Romney was a 'phony,' declined to use the word.

'I think he's a person who changed his positions on many issues,' McCain said.

A Mason-Dixon poll showed Romney at 27 percent and Huckabee at 23 percent in Iowa, both trailed by McCain, Fred Thompson, Rudy Giuliani and Ron Paul. The polls had a margin of error of plus or minus 5 percentage points. On the Democratic side, the poll showed Edwards, Clinton and Obama all within a percentage point of each other.

Clinton told ABC that her husband, former President Bill Clinton, would take on the same responsibilities as traditional presidential spouses if she won the election.

'He will not have a formal, official role, but just as presidents rely on wives, husbands, fathers, friends of long years, he will be my close confidant and adviser as I was with him,' she said on 'This Week.'

4 days to Iowa caucuses, Huckabee calls Romney dishonest, Obama comments on criticism

The idea of her husband participating in National Security Council meetings 'wouldn't be appropriate,' she added.

Laughing, Edwards said he couldn't imagine Bill Clinton staying out of the mix.

'I think it's a complete fantasy,' he said on CBS. 'If you watch him out on the campaign trail, he spends an awful lot of time talking about his views and not Senator Clinton's.'

In the GOP race, Huckabee's surge to the top tier has forced him to answer questions about his record in Arkansas, a series of gaffes on the campaign trail and the role his faith - he's an ordained Baptist minister - plays in his public life.

'The key issue to real faith is it can never be forced on any one,' Huckabee said, adding that he would have no problem appointing atheists to government posts.

Judge him by his record in Arkansas, he said: 'I never proposed a bill that would remove the capitol dome and replace it with a steeple.'

Huckabee, a long-time opponent of legalized abortion, said he does not believe that women should be punished for undergoing the procedure, but that doctors might need to face sanctions when they 'take money to take life.'

Thompson criticized Huckabee's missteps in discussing the turmoil in Pakistan after the assassination of former Prime Minister Benazir Bhutto.

'His ideas now are not consistent with someone who understands the nature of the world that we live in and the challenges that we face,' Thompson said on 'Fox News Sunday.'