Everything You Need to Know About the U.S.-Japan Defense Treaty Irking Trump

(Bloomberg) -- A longstanding defense treaty between the U.S. and Japan is the latest international agreement to attract the ire of President Donald Trump. He is said to have mused about withdrawing from the treaty because he sees it as one-sided, since it promises U.S aid if Japan is ever attacked but doesn’t oblige Japan’s military to come to America’s defense. A U.S. withdrawal would represent a fundamental shift in an alliance that has helped guarantee security in Asia, laying the foundation for the region’s economic rise.

1. What is the treaty?

It was first signed in 1951 along with the Treaty of San Francisco that officially ended World War Two. Revised in 1960, the “Treaty of Mutual Cooperation and Security between the United States and Japan” grants the U.S. the right to base military forces in Japan in exchange for the promise that America will defend the nation if it’s ever attacked. Under some circumstances, the treaty would include the U.S. defending Japan from cyberattacks. During the U.S. occupation after World War II, the Americans imposed a pacifist constitution that prohibited Japan from maintaining land, sea or air forces.

2. What does the U.S. get out of it?

The U.S. was initially anxious to maintain a bulwark against the communist bloc in Asia; Russian military planes still regularly fly around the Japanese coast in what experts say is an effort to monitor U.S. activity in Japan. U.S. bases in Japan, which are concentrated in the southern prefecture of Okinawa, formed a launchpad for the U.S. wars in Korea in the 1950s and later in Vietnam. The U.S. Seventh Fleet -- based in the central Japan port of Yokosuka -- has helped maintain the security and stability that’s been essential to the economic and trade growth of the region, benefiting U.S. exporters.

3. What does the treaty cost the U.S.?

Japan subsidizes the costs of maintaining the troops and is set to pay 197 billion yen ($1.8 billion) this year, although the U.S. does not publish costs of maintaining the bases. Some experts say it’s probably cheaper for the U.S. to keep its troops in Japan than to bring them home.

4. What would an end to the treaty mean?

It would risk ceding security of the Western Pacific to China and potentially spurring a fresh nuclear arms race. Shelter from the so-called U.S. nuclear umbrella has allowed Japan to avoid developing its own arsenal -- a move that would raise tensions in China and the Korean Peninsula, where memories of past Japanese aggression run deep. To get around the constitutional ban, Japan has gradually built up a military it refers to as the Self-Defense Forces and has introduced modern weaponry, much of it purchased from the U.S., with an annual defense budget of 5 trillion yen. The loss of U.S. protection, combined with the proximity of nuclear-armed North Korea and a rapidly burgeoning Chinese military, might be enough to push Japan down the nuclear route. It would also call into question the U.S.’s military commitments to Australia, South Korea, the Philippines, Taiwan and a host of other allies around the world.

5. What is Japan’s stance?

Prime Minister Shinzo Abe, whose grandfather signed the 1960 treaty, has spoken of the need to create an even stronger defense partnership with the U.S. He oversaw a 2014 reinterpretation of the constitution to allow Japan to come to the defense of an ally in certain circumstances -- a change that sparked massive demonstrations outside parliament. Abe has also increased the defense budget every year since he took office in 2012 and focused spending on expensive U.S. technology such as F-35 jet fighters and land-based Aegis missile defense equipment. Still, hemmed in by the pacifist constitution, and the social security costs associated with its rapidly aging population, Japan has little room to raise defense spending further. The shortage of young people also means Japan’s military struggles to recruit enough people to fill its ranks. Local residents often complain of noise, accidents, crime and pollution associated with U.S. bases, particularly in Okinawa.

6. What would it take to exit the treaty?

The terms of the security treaty state that either party may withdraw, and that termination would take place a year after notice has been given. It’s unclear whether a U.S. president has the authority to withdraw from such a treaty without congressional approval, although President George W. Bush pulled out of the Anti-Ballistic Missile Treaty in 2002 on his own.

The Reference Shelf

• QuickTakes on Japan’s military and Japan-South Korea tensions.
• The 1960 treaty.
• Bloomberg exclusive: Trump muses privately about ending the treaty.
• A QuickTake on Trump challenging the international order.

--With assistance from Emi Nobuhiro.

To contact the reporter on this story: Isabel Reynolds in Tokyo at ireynolds1@bloomberg.net

To contact the editors responsible for this story: Brendan Scott at bscott66@bloomberg.net, Grant Clark

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