Prime Minister Shinzo Abe’s administration is plotting another radical change in Japan’s postwar security policy.

It is laying the political groundwork for adding an aircraft carrier to Japan’s arsenal of weapons in a reckless departure from the nation’s strictly defensive security policy.

The Maritime Self-Defense Force's Izumo helicopter carrier, the largest destroyer operated by the MSDF, which went into commission in 2015, has a long flight deck like that of an aircraft carrier and is capable of carrying and deploying many helicopters.

The ship was designed with the possibility of being converted into an aircraft carrier, which can carry fighter jets. Since March, some clear signs have emerged of a serious interest in this idea within both the government and the ruling Liberal Democratic Party.

First, Defense Minister Itsunori Onodera, speaking at the Diet, admitted that the ministry is studying the feasibility of retrofitting the Izumo so that it can land U.S. F-35B stealth fighter jets.

In April, the Defense Ministry released a report compiled by a defense contractor about a study commissioned by the ministry into the possible conversion of the Izumo into an aircraft carrier that can provide rear-area support to U.S. military operations.

As if giving a boost to the government’s move, the LDP recently called for introducing a “multipurpose aircraft carrier” in its proposals for the new National Defense Program Guidelines the government plans to draft toward the end of the year.

The ruling party has claimed that the envisioned vessel would be used for “various purposes within the boundary of ‘senshu boei,’” or nonaggressive, exclusively self-defense. But there is no doubt that it would be an aircraft carrier with highly enhanced offensive capabilities.

Possessing an aircraft carrier has been a long-held dream of the MSDF, which has inherited the traditions of the Imperial Japanese Navy.

The Defense Ministry still maintains that it is only conducting a study on the idea of converting the Izumo into an aircraft carrier without working on any specific plan to carry out the idea.

Behind the scenes, however, the ministry has been taking steady steps toward having a “moving airbase.”

The nation’s successive Cabinets have stuck to the position that the war-renouncing Article 9 of the Constitution bans Japan from possessing offensive aircraft carriers, intercontinental ballistic missiles or long-range strategic bombers. This position is based on the view that if Japan arms itself with such weapons it would violate the principle that it can only have minimum necessary self-defense capabilities.

Some policymakers within the Defense Ministry argue that the envisioned aircraft carrier would not be “offensive” if it is used only for defending remote islands.

But there can be no clear line between “offensive” and “defensive” aircraft carriers.

New national security legislation has made it possible for such a ship to be deployed anywhere in the world and used as a seagoing airbase for U.S. forces. There is no way to ensure that the operations of the Izumo-based aircraft carrier will be limited to strictly self-defense missions.

Abe has been displaying a skeptical stance toward Japan’s postwar senshu boei policy.

In a Lower House Budget Committee session in February, Abe, while vowing to “hold fast to” this principle, said, “There is a very harsh reality (concerning this policy) purely from the viewpoint of our defense strategy.”

This policy could “effectively force Japan to wait until it receives a first strike from the enemy (before it can use its forces) and turn its land into a battlefield,” he warned.

But the strictly defensive security policy, combined with Article 9, which is Japan’s virtual declaration to the international community that it will never become a security threat to other countries again, has contributed to easing military tensions in East Asia.

Japan’s gradual shift away from this principle could result in a futile arms race with its neighbors.

Some officials at the Defense Ministry are critical of the idea of adding an aircraft carrier to the MSDF’s fleet.

“We don’t have the financial and human resources needed to operate an aircraft carrier,” one official says.

The security policy challenge for Japan is how to ensure peace and stability in the region with a limited budget through efforts driven by an effective combination of military and diplomatic strategies.

The government should work out a security policy agenda based on this broad perspective.

The Asahi Shimbun, June 3