The difference is that the world thought Iraq had WMDs. It wasn't a lie, it was the best we all knew at the time.
Clinton outright lied from the start.
Nope, just before Bush rushed into war "the world" did NOT believe Iraq had WMD's. Not after Hans Blix went in for the last time. Only the warmongers kept insisting there were WMD and that they knew where they were even after the WMD weren't where they told Hans Blix they would be.
You should try to follow the whole story and not just the bits you like to hear. I'll make this easy for you:
US: "Iraq has WMD"
World: "Could be yes, but they can't seem to be found, so there is no proof to go to war over really. We should at least see if we can find them."
US: "We know where they are, go look on <these locations>"
Hans Blix: "OK I'll go look"
Hans Blix: "Nothing there"
US: "Ah they must have moved them. They MUST own WMD. We sold them the damned factories and supplies so we know ---by the flying spaghetti monster's hairy nether regions!---!"
Worl: "Well we went look where you said they were and they weren't, so who is to say your not just blowing it out of your ass?"
US: "OH ---by the flying spaghetti monster's hairy nether regions!--- WE WANT TO GO TO WAR!"
World: "What on earth for?"
Blair: "My whole country disagrees, but I want to go to war too!"
US: "OH ---by the flying spaghetti monster's hairy nether regions!--- WE WANT TO GO TO WAR!"
Blair: "Oh come on let's present our case and ask the world if we should go to war"
Colin Powell: "Really we have pictures of trucks and bunkers. See? They moved things around, so they must have WMD"
World: "Ehm no sorry, that's not really convincing and neither was the "proof" you came with before. Just go home and do something about your crippled economy, poor education, health care mess and such"
US: "OH GODAMMIT WE WANT TO GO TO WAR!"
US: "Ah what the ---fudgesicle---, we just go to war anyway"
World: "You sure you're not just lying to your people about those terrorist links, WMD and all that other talk?"
US: "No problems. We know what we know and don't know what we don't know"
World: "And?"
US: "Well, uhm, eeeeehhhhmmm"
World: "And?"
US: "We went in there to free the people of Iraq"
World: "Sigh, sure"
World: "Well at least your economy is completely crapped up now so you have no money to start any other wars and our money is now worth about 50% more. That's at least something good. Too bad your mishandling of the 'peace' created thousands of extra terrorists."