From CNN last night, Blitzer pressing White House spokesman Dan Bartlett for an explanation:

"BLITZER: All right. A lot of confusion today over what the president meant when he said that the war on terror is not winnable, you can't exactly win this war. What exactly did he mean by that?"
"BARTLETT: Anybody who has heard this president the last three years has demonstrated that he understands that we can win this war on terror ... When he said we can't win it, what he is saying is that this, it, Al Qaida is not a conventional enemy, not one that's going to sign up to a treaty and say we surrender..."
"WOODRUFF: But when he was asked that almost identical question on CNN just a few weeks ago, the same question, can the war on terror be won, he said absolutely it can be won."
"BARTLETT: That's what I'm saying."
"WOODRUFF: So which is it?"
"BARTLETT: Exactly..."

Limbaugh's program this afternoon from Des Moines, Iowa,

From the transcript:

"RUSH: ... But John Edwards is out there saying (paraphrased), "A-ha! Bush is now flip-flopping, and we, John Kerry and I, we can win this, and Bush is..." What did you mean by this?

THE PRESIDENT: Well, I appreciate you bringing that up. Listen, I should have made my point more clear about what I was saying, you know, what I meant. What I meant was that this is not a conventional war. It is a different kind of war. We're fighting people who have got a dark ideology who use terrorists, terrorism, as a tool. They're trying to shake our conscience. They're trying to shake our will, and so in the short run the strategy has got to be to find them where they lurk. I tell people all the time, "We will find them on the offense. We will bring them to justice on foreign lands so we don't have to face them here at home," and that's because you cannot negotiate with these people and in a conventional war there would be a peace treaty or there would be a moment where somebody would sit on the side and say we quit. That's not the kind of war we're in, and that's what I was saying. The kind of war we're in requires, you know, steadfast resolve, and I will continue to be resolved to bring them to justice, but as well as to spread liberty -- and this is one of the interesting points of the debate, Rush, is that, you know, I believe societies can be transformed because of liberty, and I believe that Iraq and Afghanistan will be free nations, and I believe that those free nations right there in the heart of the Middle East will begin to transform that region into a more hopeful place, which in itself will be a detriment to the ability to these terrorists to recruit -- and that's what I was saying. I probably needed to be a little more articulate."

and one more:

"I think [Kerry] going to Vietnam was more heroic than my flying fighter jets. He was in harm's way and I wasn't. On the other hand, I served my country."
-- President Bush, in a "Today" show interview.