Overview

The growing number and modernization of ballistic missiles in the Asia-Pacific region poses a security challenge for the United States and its allies. Congress has expressed strong concern about the ballistic missile threat from both North Korea and Iran and strong interest in ballistic missile defense (BMD) systems to counter those threats. Section 229 of the National Defense Authorization Act (NDAA) for FY2013 ( P.L. Similarly, the FY2014 NDAA ( P.L. 113-291 ) encourage the United States to cooperate with regional allies on BMD issues to enhance the security of all partners. The configuration of sensors, command-and-control (C2) centers, and BMD interceptors in East Asia—in other words, the regional "architecture" of U.S. BMD—has slowly evolved in concert with contributions from treaty allies. Issues for Congress related to the evolution of U.S. BMD posture and policy in the Asia-Pacific region include
appropriations for BMD programs; the potential for Foreign Military Sales (FMS) financing of BMD technology to allies; the role of BMD cooperation in shaping alliance relationships and overall U.S. strategy in the Asia-Pacific region; the effect of U.S. BMD cooperation on U.S. relations with China, North Korea, and Russia; and the possible role of U.S. BMD cooperation in influencing Chinese, North Korean, and Russian military developments. U.S. BMD Policy

The stated focus of U.S. BMD policy is to defend against limited missile strikes from so-called rogue states, namely Iran and North Korea, on the U.S. homeland or against allies and U.S. forces deployed abroad. As a matter of policy, U.S. missile defenses are not intended to alter the balance of nuclear deterrence with the major nuclear-armed states, i.e. Russia and China. North Korea's Ballistic Missile Threats

Observers believe that North Korea has a large arsenal of ballistic missiles that could reach targets in South Korea and Japan. U.S. and Allied BMD Capabilities in the Region

The responses of the United States and its allies in the Asia-Pacific region to the threat of ballistic missiles have included political statements, policy coordination, changes to military doctrine, research and development programs, deployment of sensors, and procurement of ballistic missile interceptors and assets. The United States has an array of BMD assets already deployed in the Asia-Pacific region: SM-3 interceptors on Aegis-equipped destroyers; PAC-3 batteries at military bases in the theater; and early warning sensors in Japan, on land (AN/TPY-2), at sea (floating X-band radar), and in space. Japan . Australia . Russia has strongly criticized U.S. BMD deployments in Europe as targeted, at least partially, at Russia, and thus a danger to the strategic stability of nuclear deterrence. The potential for BMD programs in East Asia to strengthen the United States' alliance relationships in the region, which Beijing fears could be turned against China. Challenges, Risks, and Opportunities Arising from Increased BMD Cooperation

At present, U.S.-allied cooperation on BMD in the Asia-Pacific region follows the hub-and-spokes model of bilateral alliance relationships centered on the U.S. military. The United States and its allies share information and have commitments to mutual defense on a bilateral basis, but the multilateralism that underpins the European BMD architecture is largely absent. Section 1666 states,
It is the sense of Congress that—(1) the regional ballistic missile capabilities of countries such as Iran and North Korea pose a serious and growing threat to forward deployed forces of the United States, allies, and partner countries;
(2) given this growing threat, it is a high priority for the United States to develop, test, and deploy effective regional missile defense capabilities to provide the commanders of the geographic combatant commands with capabilities to meet the operational requirements of the commanders, and for allies and partners of the United States to improve their regional missile defense capabilities; ...
(5) the United States should continue to work closely with its allies in Asia, particularly Japan, South Korea, and Australia, to improve regional missile defense capabilities, particularly against the growing threat from North Korean ballistic missiles."
The growing number and modernization of ballistic missiles in the Asia-Pacific region poses a security challenge for the United States and its allies and is thus a concern for many in Congress. The United States has made ballistic missile defense (BMD) a central component of protection for forward-deployed U.S. forces and extended deterrence for allied security. The configuration of sensors, command-and-control centers, and BMD assets in the region has slowly evolved with contributions from treaty allies, primarily Japan, Australia, and South Korea.
Observers believe that North Korea has an arsenal of hundreds of short-range ballistic missiles and likely dozens of medium-range Nodong missiles; the extended-range Nodongs are considered capable of reaching Japan and U.S. bases there. Longer-range North Korean missiles appear to be under development but remain unreliable, with only one successful test out of five in the past 15 years. The U.S. intelligence community has not yet concluded that North Korea can build nuclear warheads small enough to put on ballistic missiles, but there is significant debate among experts on this question.
Congress has maintained a strong interest in the ballistic missile threat from both North Korea and Iran and in BMD systems to counter those threats. The National Defense Authorization Act (NDAA) for FY2013 noted that East Asian allies have contributed to BMD in various ways, and it called on the Department of Defense (DOD) to continue efforts to develop and formalize regional BMD arrangements. Similarly, the FY2014 NDAA and FY2015 NDAA encourage the United States to cooperate with regional allies on BMD issues to enhance the security of all partners.
The United States and its allies in the Asia-Pacific region have responded to the North Korean missile threat by deploying BMD assets and increasing international BMD cooperation. The United States and Japan have deployed Aegis-equipped destroyers with Standard Missile 3 (SM-3) interceptors, Patriot Advanced Capability 3 (PAC-3) batteries, early warning sensors, and advanced radars to meet the threat. South Korea and Australia have relatively basic BMD capabilities with plans to improve those in the near future. Cooperation on BMD follows the hub-and-spokes model of U.S. bilateral alliance relationships in the region; the multilateralism that underpins the European BMD arrangement is largely absent. Working-level coordination is especially close among the United States, Japan, and Australia, but senior U.S. defense officials have called for greater integration of U.S. and allied BMD efforts in East Asia to improve effectiveness.
The stated focus of U.S. BMD policy is to defend against limited missile strikes from rogue states, not to alter the balance of strategic nuclear deterrence with the major nuclear-armed states. Nonetheless, Russia and China have strongly criticized U.S. BMD deployments as a threat to their nuclear deterrents, and thus a danger to strategic stability. Chinese officials and scholars make several other criticisms: that BMD is antagonizing North Korea and thus undermining regional stability; that the United States is using BMD to strengthen its alliance relationships, which could be turned against China; and that BMD is undermining China's conventional missile deterrent against Taiwan, and thus emboldening those on Taiwan who want to formalize the island's separation from China.
Specific issues for Congress raised by BMD cooperation in the Asia-Pacific include
appropriations for BMD programs; the potential for Foreign Military Sales financing of BMD technology to allies; the role of BMD cooperation in shaping alliance relationships and overall U.S. strategy in the region; the effect of U.S. BMD cooperation on U.S. relations with China, North Korea, and Russia; and the possible role of U.S. BMD cooperation in shaping military developments in those countries.