US: With 22 days to go in a presidential race increasingly shaped by the mutual hostility of the candidates, President Bush and Democratic challenger Mr John Kerry have boiled down their campaigns to one simple message: the other guy is not credible writes Conor O'Clery in New York.
After Friday's presidential debate, the second of three, Mr Bush told a campaign rally in Iowa that Mr Kerry's claim to hold a consistent position on Iraq "just don't pass the credibility test".
Senator Kerry told supporters in Iowa that the President had lost credibility with the world over Iraq and "we need some adults running the foreign policy of the United States of America". The Massachusetts senator was judged the winner by a narrow margin of the second debate, held in Missouri, but Mr Bush helped restore Republican morale by giving a more feisty and less hesitant performance than in Florida on September 30th.
The third debate, which will be staged in Arizona on Wednesday, will focus on domestic issues, and will give the candidates a final opportunity to take the initiative in what is now a very tight race for the White House.
The Democratic challenger went into the first debate with a 6-8 point deficit but is now running level with the President in national polls and has made up ground in key states such as Ohio.
The Arizona debate will allow Mr Bush to promote the steady economic recovery of the last year, and to appeal to conservative Americans on cultural issues on which he has strong support, such as abortion.
Mr Kerry will seek to highlight job losses, the decline in healthcare, more expensive prescription drugs and the President's lack of support for stem cell research.
The Massachusetts senator is aiming to use the remaining three weeks before polling day to portray himself as a centrist, a strategy that Bill Clinton used to win the presidential election of 2002, aides say.
The first half of Friday's testy debate, during which the candidates were allowed to pace around a red-carpeted arena as they answered questions from undecided voters, focused on Iraq.
Mr Kerry tried from the outset to put the President on the defensive.
He said Mr Bush had failed to find weapons of mass destruction and had turned his campaign into a "weapon of mass deception".
When the President was asked about the report of the US arms inspector that UN sanctions had prevented Iraq from restarting his banned weapons's programmes, he said: "Sanctions were not working, the United Nations was not effective in removing Saddam Hussein."
Mr Kerry stepped in quickly to respond that, "the goal of the sanctions was not to remove Saddam Hussein, it was to remove the weapons of mass destruction". One of the most dramatic moments of the debate came when a member of the audience challenged Mr Kerry to give a solemn pledge not to increase taxes on families earning less than $200,000 a year.
In a reply similar to President H. W. Bush's "Read my lips, no new taxes" pledge in 1988 (which helped him win the election but which he subsequently broke), Mr Kerry stated: "Absolutely yes. Right into the camera. I am not going to raise taxes."
Mr Bush mocked Mr Kerry for his vow, telling supporters on Saturday that "to keep that promise he would have to break almost all of his other ones", adding that his opponent had the most liberal record in the Senate.
One questioner took Mr Bush to task for not allowing Americans to buy cheaper pharmaceutical drugs from Canada, to which he replied: "When a drug comes in from Canada, I want to make sure it cures you and doesn't kill you."
Four years earlier in the same forum Mr Bush had said he thought the idea of buying cheaper drugs from Canada "makes sense", and Mr Kerry accused him of changing his mind because he was indebted to big US pharmaceutical firms.
Mr Bush again refused to specify any mistakes during his presidency.
Asked to name three instances of a wrong decision he said: "I made some mistakes in appointing people, but I'm not going to name them". He said that historians might look back on some aspects of the war and say, "you shouldn't have done that", but he believed he made the right decision to go into Afghanistan and Iraq.
In his post-campaign rally in Iowa, Mr Bush said that several of Mr Kerry's statements were not credible. He said he could "barely contain myself" when Mr Kerry said with a straight face he had only had one position on Iraq.
"He must think we're on a different planet," said the President, echoing a charge from Mr Kerry that Mr Bush and the Vice President, Mr Dick Cheney, were the only two people on the planet not to acknowledge what was going on in Iraq.
"Who's he trying to kid?" asked Mr Bush. "He can run, but he cannot hide." Mr Bush sought to undo the damage caused by his facial grimaces in the first debate, telling the rally: "You know, after listening to his litany of complaints and his dour pessimism, it was all I could do not to make a bad face."
In Ohio Mr Kerry told cheering supporters: "The reason I thought he was making all those scowling faces was because he saw the latest job numbers."