Given the chaos that a war might unleash, what options does the world have to avoid it? One approach would be for the U.S. to accept Iran as a nuclear power and learn to live with an Iranian bomb, focusing its efforts on deterrence rather than pre-emption.

The risk is that a nuclear-armed Iran would use its regional primacy to become the dominant foreign power in Iraq, threaten Israel and make it harder for Washington to exert its will in the region. And it could provoke Sunni countries in the region, like Saudi Arabia and Egypt, to start nuclear programs of their own to contain rising Shiite power.

Those equally unappetizing prospects — war or a new arms race in the Middle East — explain why the White House is kicking up its efforts to resolve the Iran problem before it gets that far. Washington is