clipped from: www.mcclatchydc.com   

WASHINGTON — Despite President Bush's claims that Iran is pursuing nuclear weapons that could trigger "World War III," experts in and out of government say there's no conclusive evidence that Tehran has an active nuclear-weapons program.

Even his own administration appears divided about the immediacy of the threat. While Bush and Vice President Dick Cheney speak of an Iranian weapons program as a fact, Bush's point man on Iran, Undersecretary of State Nicholas Burns, has attempted to ratchet down the rhetoric.

"I don't think that anyone right today thinks they're working on a bomb," said another U.S. official, who requested anonymity because of the issue's sensitivity
Bush and Cheney's allegations are under especially close scrutiny because their similar allegations about an Iraqi nuclear program proved to be wrong.

If conclusive proof exists, however, Bush hasn't revealed it. Nor have four years of IAEA inspections.