Iran’s threat makes no economic sense. Closing the strait would shut off Iran’s main source of income and deny its people necessary imports such as gasoline, food and consumer goods. The hardships of a closure would fall mainly on the Islamic regime as the rest of the world adjusted to the temporary and relatively minor oil shortage.

Closing the strait makes even less military sense. Iran would assume the role of the aggressor and lose whatever international legitimacy it has. Perhaps Tehran thinks disrupting the regional seaborne oil trade is a justifiable response to an oil embargo or other aspects of economic warfare. There are, however, significant legal ramifications for initiating the use of overt military force in an international waterway. The United Nations could authorize member states to take whatever means necessary to reopen the strait, and even if permanent U.N. Security Council members Russia or China decide to veto such a resolution, NATO or an ad-hoc international coalition could legally take action.