For context, you might want to read the Bush's first speech on August 16th of this year.
Official White House Transcript
August 21, 2006
Speech by President Bush giving 48 hours to Iranian dictator Ahmadinejad to step down and end radiological threats from Iran
When I spoke to you last, five days ago, I announced that American forces had taken the decisive step to end the nuclear bomb threat from Iran. Our forces successfully destroyed the machinery that we know to be designed for nuclear weapons, not nuclear power. To save American lives and Iranian lives too, American forces used a fission-enhanced penetration weapon to destroy the Natanz gas centrifuge. Fission-enhanced penetration should not be considered nuclear bombing, as has been made quite clear.
Our necessary action made the mistake of the Iranian dictator equally clear. "President" Ahmadinejad brought this situation on his country by his dangerous pursuit of a new Holocaust, a nuclear Holocaust. We stopped him. History will be clear - we did the right thing.
Yesterday, President Ahmadinejad compounded his mistake. The crowds he spoke to in Tehran were brought there using a combination of force, hysteria, and lies. Whatever misleading images have been shown by the media, the Iranian people as a whole know that we want to help them, they love freedom, and they oppose their dictator.
Just a small, fanatical few support the dictator mullahs, but these few people control all the power. Fanning the hysteria, maybe even believing it himself, Ahmadinejad accuses us of attacking them with nuclear bombs. That is a lie. We did not use nuclear bombs; we used one fission-enhanced weapon. We did not start this confrontation; as stated before, our evidence leaves no doubt that Iran planned to distribute nuclear bombs to terrorists. Self-defense is not an attack.
Ahmadinejad then took a fatal step - he said in retaliation for raining "nuclear fire" on his own people, Iran will "soon" explode a radiological bomb at an American government or military facility within a major US city. The "nuclear fire" is a lie; we did not use a nuclear bomb, and all the military facilities that we hit were carefully targeted to minimize civilian casualties. Iran's dictators have no right to retaliate against something we had to do in self-defense.
While we have eliminated the greatest threat, Iranian nuclear bombs, a severe threat has now arisen from this planned "dirty bomb" attack. We have to take direct action to counter this new threat. To those who disagreed with our decision for pre-emptive self-defense in Iran, the need for self-defense should now be clear. Hindsight is not wisdom, but foresight about an open threat to our cities is simply obvious. We must remove Ahmadinejad and eliminate the threat he poses.
President Ahmadinejad has 48 hours to resign. A man this dangerous can no longer rule the country. Iran's subsequent leader must, in the same time period, renounce any plan to subject the United States to radiological attack, and open all nuclear facilities to UN inspection and inventory. If this deadline is missed, Operation Persian Freedom will begin.
We have made it clear to the Iranian people that our problem is not with them, but with the dictators who stole their country. Their freedom and sovereignty will be returned to them from the dictator mullahs who robbed them.
This dangerous world requires both courage and hope. I know our brave American soldiers have both courage and hope; I know the brave American people do as well. Moving forward today, we save Iran and save our own country.
May God bless America's work, and may God bless us all.