I believe that US foreign policy, wherever humanly possible, follow Kant's categorical imperative, if it can be understood like this...Rules are valid for me if they would also be valid for you.
If you accept this, and my example will help, the fundamental flaw with Bush's logic becomes clear, and grounds for the rejection of this policy plain.
President Musharaff of Pakistan has had some serious attempts on his life in the last few months, and although I hope his military dictatorship devolves into something stabler at the first opportunity, I do not hope the directive comes from any but the President himself.
If another attack comes, and is very succesful, Pakistan, the only acronym country on Earth, could find itself without a clear successor. Since Musharaff won the last election with ~95% of the vote, it is clear the public has not yet rallied around a replacement. This could lead to control being held by who knows whom, including, perhaps, a radical wing of the ISI-faction which was so enthused with the Taleban, earlier.
Considering that Pakistan controls nuclear weapons, which the Islamic-oriented parties would likely want to use to threaten India in their desire for Kashmir, it would follow Bush's logic for India to invade Pakistan.
In fact, if the administration of any government wants to go to war with another, the US strategy has proved that lying to your people about it is AOK.
For all intents and purposes, the entire country of Iraq was open to inspections before the war, which means Saddam was no threat, he was disarmed, he was under sanctions, he couldn't even buy a pencil, dammit.