"Dear Iran,
Sorry you guys missed such a great opportunity to attack our friends, and in our own country, gotta give you props for the balls on that one! Please refrain from any further aggression, I personally won't do anything about it, but maybe if you were not a governed state we'd fire some missiles from drones at you or something because we just can't commit troops at this juncture. Please feel free to try again when they elect a Republican with some testicular fortitude in 2012 (but wait until Jan 20, 2013 so I'm clear). Maybe then the US will retaliate against you and you can get that war of Koranic proportions you seem to be dying for. Until then, you have our condolences and hey, no hard feelings, you get an 'A' for effort!
Sincerely, you're secret friend,
Barrack Hussein Obama"

Note: Not actual letter, but I'm sure this is what it would look like.