They went in too early. Saddam is not immortal, he would have died sooner or later. WIth his death, infighting would have begun and that would've been a good time to invade, especially seeing that no WMDs were found nor a connection between Saddam and international terrorist groups (not a surprise there, Saddam was hardly interested in their endavours and vice-versa, just look at his past history for Christ's sake). Whatever the reasons for invading Iraq really were, the bottom line, in my opinion is that it happened way too early and on the backbone of terrorism phobia.