Iran’s repeated threats to close the Strait of Hormuz are a pivotal part of a military strategy based on psychological and asymmetric warfare. Blocking the strategic waterway, through which 90 percent of Persian Gulf oil flows to the outside world, would have sweeping implications for regional security and global oil markets. It may be the Islamic Republic’s most potent weapon. Tehran has also hinted it would retaliate against U.S. forces, notably the Fifth Fleet based in the Persian Gulf, if it is attacked.
Since the 1979 revolution, Iran has developed sufficient military capabilities to back up its threats. The Revolutionary Guards Navy may be able to inflict damage on U.S. forces. It operates hundreds of small and relatively fast attack boats, some armed with sophisticated anti-ship cruise missiles. Its fleet could attempt to swarm larger U.S. ships and try to penetrate their defenses, even if they could not destroy the more powerful American vessels. Iran could also fire missiles at U.S. warships from its 1000 mile-long Gulf coastline. An even more controversial Iranian move would be scattering mines either near the Strait or in the Persian Gulf, which could slow or stop shipping as the U.S. Navy tried to clear the waterways.