Little detail is currently available about the Trump Administration's agenda for missile defense and whether current policy or program direction might change. The Administration has thus far said only that it will "develop a state-of-the-art missile defense system to protect against missile-based system attacks from states like Iran and North Korea." A detailed defense budget will not be presented until later this spring, so there is uncertainty as to what precisely the BMD budget and program will look like. Ongoing BMD issues of interest to Congress are summarized below.
The FY2017 National Defense Authorization Act (NDAA, P.L. 114-328) made several notable changes that could have significant effects on the direction of U.S. BMD policy and programs. First, the NDAA modified the National Missile Defense Act of 1999 (P.L. 106-38; 10 U.S.C. 2431 note), which had emphasized deploying a national BMD system "capable of defending the territory of the United States against limited ballistic missile attack." It now reads that the United States should "maintain and improve an effective, robust layered missile defense system capable of defending the United States, allies, deployed forces, against the developing and increasingly complex ballistic missile threat" (Section 1681). Although conferees noted that the new provision does not require or direct the development of missile defenses against any country or their strategic forces, neither does the new provision restrict such development. This is important because, since the 1980s, the United States has explicitly asserted its BMD policy and programs are not directed at Russian and Chinese strategic nuclear deterrent forces. Some policy experts believe this change could have significant consequences for relations with Russia and China, while also affecting the scope of U.S. strategic nuclear and BMD programs.
Second, the FY2017 NDAA (Section 1683) encourages the Department of Defense (DOD) to examine the feasibility of defeating space-based threats to space-based U.S. national security systems and to examine the feasibility of defeating ballistic missile threats with a new generation of space-based missile defense capabilities. Although there are no prohibitions against deploying nonnuclear weapons in space, the United States has not pursued space-based BMD interceptor programs since the 1980s, and Congress has not demonstrated widespread budgetary or legislative support of such capabilities in space.
Third, the FY2017 NDAA (Section 1684) directs DOD to review and report on the full range of offensive and defensive capabilities of the United States to defeat potential ballistic missile threats. This would include the possibility of preemption as a new mission for U.S. BMD systems.
For years, Congress has expressed ongoing concern over the pace of flight tests for the Ground-based Midcourse Defense (GMD) program, indicating it would like to see such flight tests at least once per fiscal year. But that suggested pace has not taken place and this issue continues to be a perennial concern for many on Capitol Hill. A significant GMD flight test was scheduled for 2016 (this would have been the first BMD test against a ballistic missile target launched at ICBM range since the start of the missile defense program in 1985), but the Missile Defense Agency continues to delay that flight test. Also, mixed test results over the years demonstrate that the GMD system may only have a limited capability against small numbers of simple or first-generation ICBM threats according to DOD.
At the same time, the operational test and evaluation performance record of other BMD systems—such as Patriot PAC-3, Aegis BMD, and THAAD (Terminal High Altitude Area Defense)—has provided many observers with relatively greater confidence in those systems and their potential effectiveness. Those programs generally receive strong congressional support.
Many in Congress and elsewhere have sought to deploy a GMD site in the northeast United States. DOD has conducted various environmental and other studies, and a location recommendation is forthcoming. Congress has provided some initial funding to support planning and design work. Neither the Obama Administration nor the Pentagon, however, expressed strong interest citing, in part, needless cost, absence of current threat or need, and questions over the limited capabilities of GMD. There is no indication that the Trump Administration intends to continue this effort.
In 2016, the Obama Administration announced it would deploy a THAAD system to South Korea to defend against a potential North Korean ballistic missile attack. Inside South Korea, although the government backed the prospective deployment, it met considerable political opposition over issues such as effectiveness, cost, and Chinese opposition to the proposal. In the United States, some questions have been raised as to potential shared financial costs between the two countries. Most observers expect THAAD to be deployed there this year, though the possibility of an earlier-than-expected presidential election in South Korea has injected some uncertainty. The current president was impeached in December 2016 and is awaiting a court decision that will determine whether she will be removed.
In 2009, the Obama Administration announced the European Phased Adaptive Approach (EPAA) as the U.S. contribution to NATO's territorial BMD mission against a potential Iranian missile threat to Europe. Phase 1 and Phase 2 of that effort is complete, and the United States has deployed an Aegis BMD capability at sea in the eastern Mediterranean, a THAAD radar in Turkey, and an Aegis Ashore BMD capability in Romania. Phase 3 of the EPAA is reportedly on track for completion by 2018; it will include a second Aegis Ashore site in Poland, as well as upgraded Aegis BMD capabilities at sea and ashore in Romania. The Trump Administration has not given any indication that it intends to alter this schedule.
Since 2010, the Obama Administration had sought to integrate existing BMD capabilities among various U.S. allies in both the Asia Pacific and the Persian Gulf, setting forth plans for increased cooperation and expansion of BMD system capabilities in those regions. Those efforts played out slowly, however, primarily because of historical distrust between some regional allies. The Trump Administration has not indicated whether it intends to continue such efforts.