Bush made it clear in his last press conference the change in arguements about why we are in Iraq:
First, they claimed the threat of Iraq attacking us with WMDs.
Second, when WMDs were not found and proven not to exist (no labs that could create them), they switched to spreading democracy.
Now, they are claiming that Saddam wanted to attack us. That this desire was enough.
Don't you think that if Saddam wanted to attack the US so bad, he would have done it when Cheney and Rumsfield gave him WMDs during the Nixon administration? Isn't that proof that the intent was never there either?