The world has grown used to chest-thumping by Tehran, and there was nothing particularly noteworthy about the exercises conducted by Iranian armed forces last week to demonstrate their ability to close the Strait of Hormuz. But how the U.S. reacts to the threats is crucially important.
Iran's large arsenal of mines would certainly present a challenge to shipping in the region if Tehran makes good on its threat. Iran has the ability to lay mines from many platforms: small boats, combatants, submarines, midget submarines, even merchant ships. And Western navies, including America's, have long underinvested in minesweeping technology. The U.S. Navy and its allies would be challenged, therefore, to sweep the strait clear of mines laid in large numbers.
But there is no doubt that the United States can prevent Iran from closing the shipping route, through which much of the world's oil travels. The U.S. and its allies could ultimately clear traffic lanes and destroy Iranian vessels attempting to lay minefields. As long as the major stakeholders in the global economy remain confident that the U.S. and its allies will keep the strait open, the impact of any Iranian attempt to close it will probably be mitigated.
It is important, therefore, for the United States to declare its commitment to using all necessary force to keep the Strait of Hormuz open. Such a declaratory policy would be explicitly defensive: If Iran violates international law by attacking shipping in transit through the strait, the U.S. will act in defense of international law to stop the illegal action and eliminate the capabilities of the violator to persist in such behavior.
Tehran would portray any such declaration as an act of aggression on the part of the "global arrogance" — as it calls the United States — and an escalation in the conflict. The Iranian regime has illegally seized a series of small islands in the strait belonging to the United Arab Emirates, and it uses them to claim that the whole Strait of Hormuz is Iranian territorial water. But even if Iran rightfully owned those islands, the argument that they constitute an archipelago under the principles of maritime law sufficient to grant Iran sovereignty over the strait is tenuous if not nonsensical.
International law has settled the question of who owns the strait: no one. All nations have the right of free transit for both military and civilian ships and aircraft. That is one reason it is important for the U.S. to announce its commitment now to defending international law by force if necessary.
Another reason to make such a declaration now is to ensure that Iranian bombast does not rattle the shaky global economy. The threat to close the strait is a form of terrorism aimed at generating a response based on fear rather than fact. The effectiveness of the terrorist tactic can be significantly reduced if the U.S. reassures the world that it can and will do what is necessary to keep international waterways open.
The last reason to make a strong declaration now is to eliminate one possible source of confusion between the U.S. and Iran during a time of rising tension. No American president would have any choice but to reopen the Strait of Hormuz and destroy Iran's ability to threaten it further. But as tension between the U.S. and Iran increases, the risk of miscalculation will also increase. This is one of those moments when stability is best served by what might seem a provocative statement. The Iranian leadership at every level must be convinced that any attempt to close the strait will both fail and lead to disaster for Iran. The more the U.S. and its partners do to drive that fact home in Tehran, the less likely Iran's leaders will be to try.
Iran's leaders, finally, will look to actions behind America's words. Now is the time to concentrate additional American naval and air power in the Persian Gulf region, as well as ensuring that U.S. forces already there have all necessary means of reconnaissance and surveillance to avoid surprises. If America's ability to clear mines in the Strait of Hormuz is insufficient — as it appears to be — then we should immediately invest in that capability ostentatiously.
Some, even outside Tehran, would portray such actions as an escalation of conflict. They would not be. We must respond to provocation with absolute reassurance to the world that we will keep the strait open and with a stern warning to the Iranians that any attempt to close it will inevitably and disastrously fail. Displaying any kind of hesitation at this moment would be the real and dangerous provocation.
Frederick W. Kagan is a resident scholar and director of the Critical Threats Project at the American Enterprise Institute for Public Policy Research.