US President George W Bush has issued an uncompromising message to voters in a rare extended television interview.
The usual studio set was switched for the Oval Office
Mr Bush said he was a "war president" and the top issue for voters should be the use of American power in the world.
He told NBC's Meet the Press that the US should accept greater spending because the nation was at war.
His appearance, ahead of the November presidential election, comes as US polls suggest his approval rating has dropped below 50%.
Senator John Kerry, who won two more state votes for the Democratic nomination on Saturday, had a lead of five-to-seven points over Mr Bush in two recent polls.
Mr Bush defended the invasion of Iraq, saying it was a "war of necessity".
He said he had not called Saddam Hussein an "imminent threat" but said it would have been too late if the US had waited until the danger was that close.
"I'm a war president. I make decisions here in the Oval Office in foreign policy matters with war on my mind," he said.
"I see dangers that exist and it's important for us to deal with them."
He defended the intelligence that indicated Iraq had or was developing weapons of mass destruction.
"The evidence I had was the best possible evidence that he had a weapon," he said.
Challenged by interviewer, Tim Russert, that no weapon had been found, Mr Bush replied: "What wasn't wrong was the fact that he had the ability to make a weapon."
The president said the arms could have been destroyed, moved or hidden.
Though Mr Bush often takes one or two questions from reporters at functions, he rarely holds longer news conferences. Correspondents note that even then he does not generally tolerate the sustained questioning and follow-ups of the Meet the Press show.
Time to judge
The president said the inquiry he has launched into the US' intelligence gathering was not looking for scapegoats.
He said it would be to learn lessons from the wars in Afghanistan and Iraq to help future decisions about countries such as Iran and North Korea, once labelled by Mr Bush as part of an "axis of evil".
While the Iraq war was necessary in part because Saddam Hussein was a "madman", the use of force was not always necessary to deal with rogue states, he said.
In North Korea, for example, he said "the diplomacy is just beginning".
He stressed the US public would have plenty of time to judge his role, though the intelligence commission will not report until March 2005, months after the presidential election.
A British inquiry into the pre-war intelligence is expected to report this summer but Mr Bush defended the 14 months he is allowing for findings, saying it should not be "hurried".
When it does come time to vote in November, he said he thought the biggest issue would be "who can properly use American power in a way to make the world a better place".
He acknowledged that the economy was also important, and said it was strong despite a record deficit.
"It's important for people who watch the expenditures side of the equation to understand we are at war," he said.
On his own military service, Mr Bush criticised the senior Democrats who have suggested that he did not show up for duty in the Alabama National Guard in 1972 where he served during the Vietnam era.
"They're just wrong. There may be no evidence, but I did report; otherwise I wouldn't have been honourably discharged," he said.
Mr Kerry, meanwhile, could win the support of another state to be the official Democrat challenger to Mr Bush in November, with Maine holding caucuses on Sunday.
He won victories in another two caucuses in Washington state and Michigan on Saturday.
His rivals hope a tougher test will come on Tuesday with votes in Tennessee and Virginia - states from the Old South of the Civil War era where some perceive the Massachusetts senator as vulnerable.