These are all risks that the U.S. military is acutely aware of, and they are magnified because of the likely lack of support from any allies—aside from Israel—for U.S. operations against Iran. The United States could still successfully strike targets in Iran, but it is far from clear that such attacks would bring major concessions from the regime. The president would be well advised to take these considerable risks and costs into account before starting a war without an obvious exit strategy.