The Trump administration last week released its Missile Defense Review (MDR). It acknowledges the mounting threat posed by countries such as North Korea and Iran, as well as the modernization of strategic forces in China and Russia. As a solution, the report harkens back to the vision of President Ronald Reagan, who sought to protect the United States from missile attack with an impenetrable shield. “Star Wars” was dismissed as both fantastical and dangerous: Its goals exceeded the capabilities of existing technology and threatened an arms race between the U.S. and its adversaries. That constraint and that danger persist.
Congress requires every administration to detail its missile defense strategy, plans and priorities; this document provides insight into the government’s security and defense thinking. The MDR should have been published a year ago but was delayed as the Pentagon sought to keep pace with a changing international environment and the president’s evolving thinking. The delay means that much of the MDR’s content is known; the contours of the strategy have been evident in budgets and speeches by senior officials. Yet the language of the MDR remains striking. It notes that the security environment is “more complex and volatile than any we have experienced in recent memory,” with potential adversaries “investing substantially” in missile capabilities. They are increasing the capabilities of existing systems, adding new and unprecedented types of missile capabilities, and integrating offensive missiles into their planning.
The report identifies North Korea as an “extraordinary threat” to the U.S., with investments in nuclear and missile capabilities to be able to threaten the U.S. homeland. Pyongyang has accelerated efforts to field missiles that can threaten U.S. forces and those of its allies — including Japan — and warns that nuclear weapons could be used in the event of a conflict in Asia. According to the report, “China seeks to displace the United States in the Indo-Pacific region and reorder the region to its advantage,” and its nuclear and missile capabilities “play an increasingly prominent role” in that effort. It uses those capabilities to also deny the U.S. the ability to protect is allies and partners in Asia; the report adds that China’s conventional ballistic missiles are a key part of that strategy.
Traditionally, the U.S. has used missile defenses to defend against “rogue threats” — a small adversary that could only attack with one or a small number of missiles. That reflected two constraints: The technological fact that defenses could be quickly overwhelmed and the belief that adversaries like Russia and China would react to systems that blocked their strategic arsenals by building more weapons or using those weapons earlier in a conflict to ensure that they would not be neutralized. The U.S. would use the prospect of massive retaliation — mutual assured destruction — to deter them. In other words, missile defense threatened to make the use of nuclear weapons more likely and even more devastating.
While the Trump administration says that missile defense remains “primarily postured to stay ahead of rogue threats” and that it will continue to rely on deterrence to constrain the behavior of China and Russia, officials disavow any intention to limit missile defense to smaller actors. Indeed, the MDR appears to resurrect the grand ambitions of the Star Wars program in defiance of those two restraints. The MDR says that the administration will try to install sensors in space to track missiles upon launch and study weapons that can shoot them down from space, along with technologies that would destroy missiles just after launch, when they are most vulnerable. Those steps require considerable progress.
In addition, and more realistically, the report calls for increasing from 44 to 64 the number of ground-based interceptors in the U.S. to defend the homeland. Allies are urged to develop their own air and missile defense platforms — supporting Japan’s decision to deploy Aegis Ashore — and the U.S. will deploy more mobile defense systems, such as the Terminal High Altitude Aerial Defense (THAAD) system in South Korea.
Strengthening regional missile defense systems makes eminent sense. That is a realistic response to threats that, while alarming, remain limited in nature. The dream of a shield that would protect the U.S. homeland against nuclear attack from more formidable adversaries remains just that: a fantasy. The price tag for a technology that has been perennially beyond reach is in the trillions of dollars. The physics and the math that favor the offense is unchanged: An attacker must only have one warhead get through to be successful; a defender must defeat 100 percent of those missiles. And it is much easier and cheaper to accelerate efforts to defeat a missile defense system. Missile defense is seductive, but it remains a distant hope.
Realistic thinking should prevail over that dream.