Iran policy is a bet-the-society decision amidst lousy intelligence. Basically, the President can elect to allow the Iranians to acquire nuclear weapons and hope a stable detergence regime can be developed, or he can resort to non-decisive action (bombing or sanctions). Presumably, invasion followed by an insurgency is off the table due to lack of the necessary force structure and political support.
The last time the U.S. or Britain faced a decision of comparable importance is when George VI had to decide whether to send for Halifax or Churchill or Lincoln had to decide whether to withdraw the garrison from Sumter.
I'm glad I don't have to decide. I've always thought of 43 as the modern Harry Truman -- a courageous, inarticulate unpopular guy who has to hammer out a war-winning strategy without experience or obvious precedents. Also, he has the rotten luck to be President now. He's got Hoover's or Buchanan's luck.
I think using detergence to wash out the Iranian regime is a great idea.