In an interview with ABC's Charles Gibson slated to air today, President Bush says he was unprepared for war when he assumed the White House and that his biggest regret of the past eight years is the faulty intelligence indicating Saddam Hussein possessed weapons of mass destruction.

"Well, I think I was unprepared for war," Bush said when Gibson asked what he was most unprepared for in his presidency.

"In other words, I didn't campaign and say, 'Please vote for me, I'll be able to handle an attack,'" Bush said. "In other words, I didn't anticipate war. Presidents -- one of the things about the modern presidency is that the unexpected will happen."

Bush also said that "the biggest regret of all the presidency has to have been the intelligence failure in Iraq."

Critics of the Iraq war have accused Bush and his administration of using the faulty intelligence to coerce lawmakers and the public into supporting his plan to invade.

"A lot of people put their reputations on the line and said the weapons of mass destruction is a reason to remove Saddam Hussein," Bush said. "It wasn't just people in my administration; a lot of members in Congress, prior to my arrival in Washington D.C., during the debate on Iraq, a lot of leaders of nations around the world were all looking at the same intelligence. And, you know, that's not a do-over, but I wish the intelligence had been different, I guess." Gibson had asked what Bush's one "do-over" would be if he had the chance.

Bush said it is difficult for him to speculate whether the Iraq war would have happened if intelligence reports had reflected that Hussein had no weapons of mass destruction, as was later discovered to be the case.

"You know, that's an interesting question. That is a do-over that I can't do. It's hard for me to speculate," Bush said.