Why is the US delaying an attack on Iran?

Thank God, the U.S. have not attacked Iran. Another Middle East war is the last thing the U.S. needs. Apart from the facts that a) Congress would have to decleare war and vote to authorise the president to conduct a war and b) Saudi Arabia is not a treaty ally of the U.S., the U.S. has no obligation to defend Saudi Arabia and c) there is no proof that Iran actually did - as said apart from these facts - a war would mean that the oil export from the Gulf would come to a stop, the instracture of Saudi Arabia and the UAE would be destroyed, especially the destruction of seawater desalination plants would have horrible consequences, and finally a war against Iran would mean huge losses in both blood and treasure.

That war could cost the U.S. thousands of casualties and probably a trillion in dollars.

Are these enough reasons for you not to go to war?