President Bush said in an interview broadcast Monday that the war on terrorism cannot be won in the traditional sense of victory, one in a series of statements he has made in the past few days to lower public expectations and mitigate political problems before he reintroduces himself to the nation Thursday night.

Bush has given a spate of interviews in the run-up to this week's Republican National Convention in New York, and he was asked by Matt Lauer of NBC's "Today" show, in an interview taped Saturday in Ohio and shown on the convention's opening day, if the war on terrorism can be won.

"I don't think you can win it," Bush said. "But I think you can create conditions so that those who use terror as a tool are less acceptable in parts of the world. Let's put it that way."

The president said he would accomplish this goal with a two-pronged strategy, which he said is to find terrorists "before they hurt us" and to "spread freedom and liberty."

Bush has made optimism a major theme of his campaign, and Democrats pounced on the remark to label him defeatist. Bush aides said the president was simply being realistic about what the United States and its allies can achieve in going after terrorist groups. But the president was far more audacious in the past in pledging to lead the war on terrorism.

Last month in Pennsylvania, he said he had "a clear vision and a strategy to win the war on terror." In February, he said, "We're going to win the war on terror." During his now-famous speech aboard an aircraft carrier declaring the end of major combat operations in Iraq, Bush said: "The war on terror is not over, yet it is not endless."

But as he prepares for what is certain to be a bruising fall campaign against Democratic challenger John F. Kerry, Bush is amending or recasting some of his most important policy positions and has begun to acknowledge for the first time that he made some mistakes.

Bush said at a news conference in April that he could not think of a single mistake he had made in confronting Iraq, yet he said in an interview with the New York Times last week that he made a "miscalculation of what the conditions would be" in postwar Iraq. In this week's issue of Time magazine, he said he asks more questions about intelligence to "make sure that the analyst who came up with that information has gotten additional input."

In explaining Bush's latest comments on whether the war on terrorism is winnable, White House press secretary Scott McClellan told reporters on Air Force One that Bush was trying to make the point that it may not be possible to win the war "in the conventional sense."

"I don't think you can expect that there will ever be a formal surrender or a treaty signed, like we have in wars past," McClellan said.

Kerry's running mate, Sen. John Edwards (N.C.), issued a strong response to Bush: "This is no time to declare defeat."

Sen. Joseph R. Biden Jr. (D-Del.), the ranking Democrat on the Foreign Relations Committee and a Kerry supporter, said in a conference call that he hoped Bush had misspoken. Biden said the war "is winnable -- it needs a strategy."

"To suggest that the war on terror is not winnable is absolutely, totally, thoroughly unacceptable," Biden said.

Bush answered questions for 90 minutes at a roundtable staged by his campaign in Nashua, N.H., twice the length of many of his events. Then he spent the night on the road -- a rarity for this homebody president -- in Michigan as he continued a tour of swing states en route to the convention.

In keeping with efforts at the convention to portray a softer side of Bush, he told the crowd in New Hampshire that no administration "has empowered more women in positions of power than the Bush administration has done." Asked about negative perceptions of him, Bush told WMUR-TV in Manchester, "Perhaps it's because I've made some hard decisions."

Bush continued rehearsing and polishing his acceptance speech, in which he plans to promise a better and more hopeful America through improvements to education, health care and retirement, and to bill himself as a transformational leader intent on reforming government at home and spreading liberty abroad.

Road-testing themes from the address, Bush reformulated a line from his speeches in the 2000 campaign when he challenged the notion that some pupils cannot learn and should simply be moved through the system. "That's not good enough for a better America," he said. "That's not good enough for a hopeful America."

As prominent Republicans continued to gossip about rumors -- flatly denied by the White House -- that Vice President Cheney would be replaced on the ticket at the last minute, Bush said he had talked to Cheney in the morning. "He's getting ready to crank it up," Bush said. Then he added a standard line about Cheney that is designed to denigrate Edwards: "I admit it, he's not the prettiest face on the ticket. I didn't pick him for his looks. I picked him because of his experience, his judgment and because he can get the job done."

In an accusation immediately denied by the Kerry campaign, Bush said in Nashua, "What I'm telling you is we're not going to nationalize health care under George W., and my opponent is, see. That's the difference. My opponent will; we won't."

Opponents rarely get called on at the carefully screened "Ask President Bush" events, but the president was asked to defend his assertion in 2002 that Israeli Prime Minister Ariel Sharon is "a man of peace." Bush said Sharon "is defending his country against terrorist attacks, just like we will."

President Bush addresses a crowd in Taylor, Mich., as part of a campaign swing in the Midwest leading up to the Republican National Convention.Bush takes a question on health care during an event in Nashua, N.H.As Bush campaigned in Michigan, delegates to the Republican National Convention, such as Michael Quevedo of Texas, gathered in New York for the convention's opening day.