The efforts by North Korea and Iran to develop ballistic missiles capable of targeting not only its regional adversaries but the U.S. homeland are intensifying. Two days ago, it directly challenged the new U.S. Administration and the international community, by testing what may be a new intermediate-range ballistic missile at the exact time that President Trump and Japanese Prime Minister Abe were meeting in the United States. Iran has test-fired two ballistic missiles in the three weeks since President Trump was inaugurated. While these launches clearly carry a political message, they also starkly underscore how swiftly these two nations are moving to pose an existential threat to the United States.

The image of North Korea as a backward totalitarian state, unable to feed its people and lacking modern technologies is not true when it comes to ballistic missiles and nuclear weapons. Pyongyang has been working on ballistic missiles and nuclear weapons for nearly thirty years. It deployed its first operational ballistic missile, the Rodong, in 1990 and may now have fielded as many as 100 ballistic missiles of various ranges. It has twice successfully employed a space launch vehicle, the classic predecessor to an intercontinental ballistic missile (ICBM), to put satellites in orbit, most recently in February 2016. It has successfully launched a ballistic missile from a submarine, something only the five major nuclear powers had previously done. Pyongyang even is developing a road-mobile ICBM, the KN-O8, something only Russia has ever done. North Korea has to date conducted at least five nuclear tests of increasing sophistication. It is busily working on miniaturization technologies necessary to putting a weapon of mass destruction (WMD) on the end of a ballistic missile. According to the head of North American Aerospace Defense Command, "It's the prudent decision on my part to assume that [Kim Jong Un] has the capability to miniaturize a nuclear weapon and put it on an ICBM."

The Iranian ballistic missile program can trace its roots back to the era of the Shah. The regime in Tehran has been working assiduously on its ballistic missile capabilities since its 1980s war with Iraq. Today, Iran has deployed one of the world’s largest arsenals of medium and intermediate-range ballistic missiles capable of holding at risk U.S. and allied targets in the region, including Israel. There are reports that Iran has received assistance with its missile program from China, North Korea and even Russia.  Last year, Iran too tested what appears to be a space launch vehicle. In the opinion of former Director of National Intelligence, James Clapper, “Iran’s ballistic missiles are inherently capable of delivering WMD, and Tehran already has the largest inventory of ballistic missiles in the Middle East.”

Iran’s nuclear weapons program is currently being held in abeyance, one hopes, as a result of the Joint Comprehensive Plan of Action (JCPOA), the agreement between the five permanent members of the United Nations Security Council, Germany and the European Union and Iran to freeze or cut back many of the latter’s nuclear activities for ten years. The JCPOA did not address Iran’s ballistic missile program. Though there are other “impediments” in place that in theory could contain Iran’s nuclear ambitions it is hard to not to see a future less than ten years hence when Iran will be able to resume its nuclear weapons program and marry warheads to future, more capable and longer-range ballistic missiles.

The U.S. Department of Defense has been working on developing counters to ballistic missile threats since the mid-1980s. Over time, the Pentagon was able to develop the capability to “hit a bullet with a bullet,” the essential task of any missile defense system. U.S. tactical and theater ballistic missile defenses have an impressive track record of successful intercepts. Today, the United States is deploying multiple missile defense systems on land and at sea including the Army’s Patriot missile and Terminal High Altitude Area Defense (THAAD) system, the Navy’s Aegis ballistic missile defense system (BMDS) with the Standard Missile (SM)-3 and the National Missile Defense (NMD) system with its Ground-Based Interceptors.

The United States is employing its missile defense capability as a political and military counter to North Korea and Iran’s ballistic missile programs. The European Phased Adaptive Approach (EPAA), intended to protect Europe from Iranian long-range ballistic missiles, is being deployed. The EPAA consists of a land-based version of the Aegis BMDS with the SM-3.  The first phase of the planned deployment has been completed with an Aegis radar and 24 SM-3 Block IA missiles based in Romania. In 2018, an additional Aegis radar and set of SM-3 missiles will be deployed in Poland. In addition, the Navy is on a trajectory to deploy more than 80 Aegis BMDS-capable ships which can provide protection not only for the fleet but land targets as well.

The current plan is to continually upgrade the Aegis BMDS with more capable radars and battle management systems and to deploy ever-more capable variants of the SM-3 so as to be able to intercept longer-range faster flying ballistic missiles. The improved SM-3 Block IB is currently being deployed. An even more capable interceptor, the SM-3 Block IIA with a longer range and improved kill vehicle is a co-development program between the United States and Japan. Ironically, the successful first intercept test of the Block IIA was conducted on February 4, 2017.

The U.S. has done something similar with the THAAD system. Responding to North Korean tests of longer-range ballistic missiles, the United States first deployed a THAAD battery to Guam. The new Secretary of Defense, James Mattis, reconfirmed a plan formulated in the final year of the Obama Administration to deploy a THAAD battery to South Korea. Since 2016, the United Arab Emirates has operated a THAAD battery.

There are a number of steps the United States could take with respect to missile defenses to both send a strong message to North Korea and Iran while also posing a military counter to its growing ballistic missile threats. First, the THAAD deployment to South Korea must be completed. This goal is complicated by the political situation in Seoul. Nevertheless, the deployment of THAAD would send a strong message to all the capitals of East Asia. Second, the Trump Administration should consult with Japan about accelerating the SM-3 Block IIA program.  Third, consideration should be given to the possibilities of deploying Aegis Ashore sites to the Persian Gulf area and on allied territory in North Asia. Finally, President Trump and Secretary Mattis should look at current plans by the Missile Defense Agency to improve the capabilities of the NMD system. It may well be time to begin building a Third Site for the NMD system in the Eastern United States to better defend the homeland against an Iranian ICBM.

Dr. Dan Goure is a Vice President of the Lexington Institute. He served in the Pentagon during the George H.W. Administration and has taught at Johns Hopkins and Georgetown Universities and the National War College. You can follow him on twitter @dgoure and you can follow the Lexington Institute @LexNextDC.