The Abe administration will treat the participation by Japanese makers in the U.S.-led global parts-sharing system for F-35 stealth jet fighter production as an exception to Japan’s long-standing three-point ban on weapons exports.

The decision violates the spirit of not only the weapons export ban but also the war-renouncing Article 9 of the Constitution.

The government has been weakening the ban through a series of decisions. The minimum that Japan should do now is demand that the parts-sharing system — the Autonomic Logistics Global Sustainment scheme — operate strictly in a transparent manner. More importantly, the government should adopt a measure to strengthen anew the ban on weapons exports.

The United States, Britain, Italy and six other countries are jointly developing the Lockheed Martin F-35 Lightning fighter. Mitsubishi Heavy Industries Ltd., Mitsubishi Electric Corp. and IHI Corp. plan to make fuselage, radar and engine parts. Parts pooled in the 10-member ALGS — which comprises the U.S., Canada, Israel, Britain, Italy, Netherlands, Norway, Denmark, Turkey and Japan — will be provided to any member country immediately whenever necessary.

In 1967, Prime Minister Eisaku Sato set down the weapons exports ban by declaring in the Diet that Japan would prohibit weapons exports to communist countries, countries subjected to arms embargoes under U.N. resolutions and countries involved in or feared to be involved in international conflicts.

In 1976, Prime Minister Takeo Miki strengthened the ban by banning the export of weapons to all countries. The ban follows the spirit of Article 9 of the Constitution.

But the government allowed Japanese makers to provide weapons technology to the U.S. in 1983 and to take part in the joint development with the U.S. of a missile defense system in 2004. The Democratic Party of Japan government led by Prime Minister Yoshihiko Noda in 2011 decided to permit the joint development and production of defense equipment with other countries if the projects contributed to Japan’s defense.

The problem with the Abe administration’s decision is that the ALGS includes Israel, which has tense relations with Iran and other Middle East parties and the possibility of war cannot be ruled out. In such a case, Japan would become involved in an international military conflict, albeit indirectly.

In making the 2011 decision, the DPJ government upheld the principle of not encouraging international conflicts. But most deplorably the Abe administration has dropped this principle. Instead it said that the government will maintain the principle as a pacifist nation. If it says so, it must make diplomatic efforts and international contributions that suit the principle.

Apparently behind the Abe administration’s decision is its intention to help advance the technological foundation of Japan’s defense industry, which some fear is weakening, and to assist the financially strapped U.S. through lower production costs made possible by international cooperation. But the decision could lead to a situation in which some countries or groups will regard Japan as their enemy, thus making Japan vulnerable in diplomatic and security fields.

For both moral and political reasons, Japan should maintain its weapons export ban and avoid becoming a merchant of death.