Photo/IllutrationPresident Donald Trump speaks about the U.S. missile defense doctrine on Jan. 17 at the Pentagon. (AP Photo)

U.S. President Donald Trump’s new missile defense strategy has raised the disturbing prospect of a futile arms race in space.

The Trump administration has released its Missile Defense Review, a document describing the U.S. medium-term strategy for missile defense.

The previous missile defense review, announced in 2010 by then President Barack Obama, focused on the threats posed by ballistic missiles developed by North Korea and Iran.

But the new strategy is marked by its emphasis on the active use of space to counter hypersonic weapons and other new military technologies being developed by Russia and China.

Hypersonic weapons are systems that are capable of traveling at speeds of Mach 5 or faster and difficult to be detected or intercepted by ground-based radar systems.

The new review calls for deploying space-based sensors to detect missile launches and track flying missiles along with space-based interceptors to destroy them immediately after they are launched.

But shooting down missiles flying at such high speeds is a formidable technological challenge, to say the least, and it is anyone’s guess as to how much money is needed to develop such a system.

There can be no space-based missile defense system capable of providing a reliable shield against high-speed missiles for the vast expanse of the United States and its allies.

In the 1980s, the administration of President Ronald Reagan proposed its Strategic Defense Initiative, or the “Star Wars” missile defense program, to protect the United States from the Soviet Union’s nuclear missile attacks. But the idea was quietly dropped as the Cold War ended.

It is possible the Trump administration’s new missile defense strategy is aimed at forcing Russia and China to knuckle under by imposing excessive military burdens on them, in line with the strategy Washington adopted in dealing with the threats posed by the Soviet Union.

If so, then the administration is clearly misreading the workings of international relationships in the post-Cold War world, which are far more interdependent than they used to be.

What is particularly worrisome is the Trump administration’s view that Japan is the most powerful partner for the U.S. missile defense efforts, underscored by Trump’s demand that Tokyo shoulder a larger security burden as a key U.S. ally.

Japan has already decided to introduce two Aegis Ashore land-based missile defense systems at a cost of 122.4 billion yen ($1.11 billion) each. Data gathered by these systems will undoubtedly also be used for efforts to defend the U.S. homeland.

The new review could lead to Washington’s calls on Japan to share more of the burden and play a larger role for the U.S. missile defense system.

Last autumn, the Trump administration announced that the United States was leaving the 1987 Intermediate-Range Nuclear Forces Treaty with Russia, saying Moscow has been violating the treaty with the development and deployment of a new cruise missile.

The move was, in part, prompted by Washington’s concerns about the threats posed by China, which is not bound by the treaty.

But Trump’s tendency to ignore the importance of efforts for arms control and mutual trust among powers and his policy of countering force with force could heighten regional tensions.

Even if it is true that China and Russia are enhancing their military capabilities and making moves that run counter to the principle of the peaceful use of space, a military confrontation between the Japan-U.S. alliance and the China-Russia camp in East Asia would serve no one's interests.

Japan should keep its distance from Trump’s missile defense strategy and assume the role of putting the brakes on an escalating arms race in space.

--The Asahi Shimbun, Jan. 22