The Overlooked Iranian Missile Threat

Iran’s brazen tests of ballistic missiles in recent months highlight a glaring failure of its nuclear agreement with Western powers, agreed to only months ago. But the focus on Tehran’s ballistic missiles overlooks an important point: Iran already possesses cruise missiles capable of delivering a nuclear warhead. Neither the nuclear agreement, nor the U.N. Security Council resolution endorsing it, mention cruise missiles despite the threat they pose.

Tehran has at least a dozen nuclear-capable Russian-made Kh-55 cruise missiles, procured illegally from Ukraine around 2001. They have a range of 1,500 miles, allowing Tehran to place a warhead anywhere from Cairo to New Delhi. The regime has also copied that design to create its own Soumar missile, though it isn’t clear how many have been manufactured.

Ballistic missiles and cruise missiles can carry nuclear warheads, but in some ways the latter would be more difficult to counter. Cruise missiles have short launch times—on the order of minutes, compared with an hour or longer for Iran’s ballistic missiles. Ballistic missiles fly steep trajectories and generally follow predetermined paths, but cruise missiles have sophisticated guidance systems. That allows them to fly close to the ground and around obstacles, making them more difficult for radar to track.

To make matters worse, the nuclear deal will allow Tehran to expand its arsenal of cruise missiles. More than $120 billion in Iranian funds was unfrozen as sanctions were lifted. U.N. Resolution 2231, which endorsed the deal, removed the categorical bans that prevented Iran from buying conventional arms and military technology that it could potentially use to deliver nuclear weapons.

Russia and China, which sold Iran much of its existing military equipment, have taken note. Their demonstrated eagerness to rebuild ties with Tehran’s defense industry suggests that Iran will have little trouble purchasing turbofan engines and guidance systems to improve its cruise missiles’ range and accuracy, and possibly new delivery platforms like bombers and upgraded strike fighters. Chinese-made antiship missiles are elemental to Iran’s strategy for contesting U.S. predominance in the Persian Gulf and Gulf of Oman. Iran fired several against U.S.-flagged oil tankers during the closing stages of the Iran-Iraq War, provided C-802 Saccades antiship missiles to Hezbollah, and test-fired two new antiship cruise missiles in recent naval maneuvers.

The U.S. should not feel powerless to play its bad hand well. Under Resolution 2231, the U.S., Britain and France can block Russia and China from transferring cruise missiles, parts and technology to Iran. Such transfers require approval from the Security Council, and the U.S. must uphold its pledge to veto attempts to give or sell Iran missile technology. The resolution also bans Iranian arms shipments abroad. Given Tehran’s history of transferring cruise missiles to Hezbollah and (likely) Hamas, it is imperative that the U.S. and its partners continue to interdict clandestine Iranian arms exports.

All permanent members of the Security Council, with the exception of China, are also party to the Missile Technology Control Regime, which was designed specifically to help prevent the proliferation of potential nuclear delivery systems like cruise missiles. This provides a ready-made forum for coordinating more stringent controls on arms exports to Iran. The U.S. should make clear that it will use existing sanctions laws to penalize violators of the MTCR.

Because these steps comply with the Iranian deal, the White House should not hesitate to take them. To prevent Iran from acquiring new cruise missiles or improving its own designs, the U.S. must move with the same sense of urgency as when it pursued the agreement in the first place.

Mr. Ruhe is the associate director, and Mr. Fleisher is a policy analyst, at the Gemunder Center for Defense and Strategy, part of the Jewish Institute for National Security Affairs. Follow Mr. Ruhe on Twitter @JCB_Ruhe.

Originally published in The Wall Street Journal on February 21, 2016