It seems that Bush might be waiting for June and July to start talking tough about Iran and doing the same thing he did with Iraq...the long drawn out attempt to go to the Security Council, etc, etc.
That would help him win the election. A successfuly Iranian Revolution right now would be too good for the Iranians and world peace. Bush would lose in November because Americans would feel that he had already won the war for them. Better to wait for the actual battle to occur next fall.