ASHINGTON, Dec. 17 — In the debate over the necessity for the war in Iraq, few issues have been more contentious than whether Saddam Hussein possessed arsenals of banned weapons, as the Bush administration repeatedly said, or instead was pursuing weapons programs that might one day constitute a threat.
On Tuesday, with Mr. Hussein in American custody and polls showing support for the White House's Iraq policy rebounding, Mr. Bush suggested that he no longer saw much distinction between the possibilities.
"So what's the difference?" he responded at one point as he was pressed on the topic during an interview by Diane Sawyer of ABC News.
To critics of the war, there is a big difference. They say that the administration's statements that Iraq had chemical and biological weapons that it could use on the battlefield or turn over to terrorists added an urgency to the case for immediate military action that would have been lacking if Mr. Hussein were portrayed as just developing the banned weapons.
"This was a pre-emptive war, and the rationale was that there was an imminent threat," said Senator Bob Graham of Florida, a Democrat who has said that by elevating Iraq to the most dangerous menace facing the United States, the administration unwisely diverted resources from fighting Al Qaeda and other terrorists.
The overwhelming vote in Congress last year to authorize the use of force against Iraq would have been closer "but for the fact that the president had so explicitly said that there were weapons of mass destruction that posed an imminent threat to citizens of the United States," Mr. Graham said in an interview on Wednesday.
As early as last spring, Mr. Bush suggested that the Iraqis might have dispersed their biological and chemical weapons so widely that they would be extremely difficult to find. And some weapons experts have suggested that Mr. Hussein may have destroyed banned weapons that he had in the early 1990's but left in place the capacity to produce more.
This week, at a news conference on Monday and in the ABC interview on Tuesday, Mr. Bush's answers to questions on the subject continued a gradual shift in the way he has addressed the topic, from the immediacy of the threat to an assertion that no matter what, the world is better off without Mr. Hussein in power.
Where once Mr. Bush and his top officials asserted unambiguously that Mr. Hussein had the weapons at the ready, their statements now are often far more couched, reflecting the fact that no weapons have been found — "yet," as Mr. Bush was quick to interject during the interview.
In the interview, Mr. Bush said removing Mr. Hussein from power was justified even without the recovery of any banned weapons. As he has since his own weapons inspector, David Kay, issued an interim report in October saying he had uncovered extensive evidence of weapons programs in Iraq but no actual weapons, Mr. Bush said the existence of such programs, by violating United Nations Security Council resolutions, provided ample grounds for the war.
"If he were to acquire weapons, he would be the danger," Mr. Bush continued, referring to Mr. Hussein. "That's what I'm trying to explain to you. A gathering threat, after 9/11, is a threat that needed to be dealt with, and it was done after 12 long years of the world saying the man's a danger."
Pressed to explain the president's remarks, Scott McClellan, the White House spokesman, said Mr. Bush was not backing away from his assertions about Mr. Hussein's possession of banned weapons.
"We continue to believe that he had weapons of mass destruction programs and weapons of mass destruction," Mr. McClellan said on Wednesday.
Mr. Bush has always been careful to have multiple reasons ready for his major policy proposals, and his administration has deployed them deftly to adapt to changing circumstances.
In trying to build public and international support for toppling Mr. Hussein, the administration cited, with different emphasis at different times, the banned weapons, links between the Iraqi leader and terrorist organizations, a desire to liberate the Iraqi people and a policy of bringing democracy to the Middle East.
When it came to describing the weapons program, Mr. Bush never hedged before the war. "If we know Saddam Hussein has dangerous weapons today — and we do — does it make any sense for the world to wait to confront him as he grows even stronger and develops even more dangerous weapons?" Mr. Bush asked during a speech in Cincinnati in October 2002.
In the weeks after the fall of Baghdad in April, the White House was equally explicit. "One of the reasons we went to war was because of their possession of weapons of mass destruction," Ari Fleischer, then the White House spokesman, told reporters on May 7. "And nothing has changed on that front at all."
On Wednesday Mr. McClellan, when pressed, only restated the president's belief that weapons would eventually be found. Mr. Bush, despite being asked repeatedly about the issue in different ways by Ms. Sawyer, never did say it, except to note Mr. Hussein's past use of chemical weapons. He emphasized Mr. Hussein's capture instead.
"And if he doesn't have weapons of mass destruction?" Ms. Sawyer asked the president, according to a transcript provided by ABC.
"Diane, you can keep asking the question," Mr. Bush replied. "I'm telling you — I made the right decision for America because Saddam Hussein used weapons of mass destruction, invaded Kuwait. But the fact that he is not there is, means America's a more secure country."