As American,British, French and Brazilian ships hold 'exercises' in the Strait of Hormuz off the coast of Iran, Barack Obama insists that he will not 'bomb' Iran if he gets into power, preferring “direct and aggressive diplomacy”.
The fear that Barack will come to power has made the Bush administration speed up its offensive against Iran and the latest naval "Operation Brimstone" is seen as a means of antagonising Iranian interests based at Bandar Abbas, believed to be the headquarters of Iran's Islamic Revolutionary Guards Corps (IRGC).
The IRGC are known to be hotheaded and provoked easily, so like a goading them might see them firing the first shots and 'validate' an attack.
The attack on Iran must therefore occur before November just in case Obama manages to secure the Presidential election. September would seem the most obvious time for an assault on Iran as it is then temperatures would be starting to drop to a lower 88ºF.

This from the Times online:
Did you know that 20% of the worlds oil is piped through there, that the price of oil is going up because of real fears that Iran will close the route if the threat from the US or Israel is too great? Surely the best way to protect Western interests would be to keep the military as far away as possible?
http://business.timesonline.co.uk/tol/business/industry_sectors/natural_resources/article4262388.ece