The president’s intervention came just weeks after leaks from a White House meeting suggested that Vice-President Dick Cheney, who is understood to favour the use of force, has regained the upper hand over the Secretary of State Condoleezza Rice and Defence Secretary Robert Gates, who both advocate diplomacy and sanctions to isolate Iran. Mr Cheney reacted with fury when the State Department suggested that negotiations might continue past January 2009, when Mr Bush leaves the White House.
So the question is: did Mr Bush last week set America inexorably on a path to the next war?
Washington officials, with close links to the Pentagon, the State Department and the National Security Council, say that the speech was designed as a threat not just to Iran, but to America’s Western allies, along with Russia and China, who have been slow to support – or who have opposed – UN sanctions against Iran. James Phillips, a Middle East expert at the Heritage Foundation, who helped devise the war-game scenario, said: "It is simultaneously a shot across Iran’s bows and an appeal for the international community to do more to stop or slow Iran’s nuclear programme."
A former White House aide added: "If this creates in the Iranians’ mind a state of fear such that they back off, that helps your diplomacy. Bush is a political poker player. To play poker, you have to know when to bluff."
Mr Bush had another reason for speaking out, too. With General David Petraeus due before Congress on September 11 to report on progress on his "surge" in Iraq, Mr Bush wanted to make the case that a withdrawal from Iraq would boost Iranian influence there – in the hope that this would increase domestic support for his policies.
In Teheran, Mr Ahmadinejad was also quick to make the Iraq connection, but as an impediment, not impetus, to American adventurism. "We have an expression in Farsi which says, ‘Bring up the one that you have given birth to first, then go for another one’," he said. "Let them do what they started in Afghanistan and Iraq then think of other countries." He dismissed threats of military action as "more of a propaganda measure than factual".