By Satoshi Ogawa, Washington Bureau; Kenta Kamimura, political reporter

The U.S. government is planning to sell more advanced weapons to Japan and the ROK. The U.S. had previously maintained that arms buildup by Japan and the ROK would heighten regional tension. The latest development may lead to a shift in the U.S.’s stance toward its alliance with Japan.

The conservative U.S. paper The Washington Times’s report on the Trump administration’s new policy stressed that “the U.S. may provide offensive weapons to Japan, a longstanding pacifist nation.” A U.S. government source told the paper that the U.S. is even considering selling Tomahawk cruise missiles to Japan.

The U.S. has sold Tomahawks only to the UK. A senior Defense Ministry official noted that it has been “cautious” about selling them to Japan. This is because many in the U.S. were concerned that Japan’s possessing its own attack capability might provoke China and undermine regional stability. The Japan-U.S. alliance has long been defined as a “spear and shield” relationship in which the U.S. provides the offensive capability, including nuclear weapons, while Japan is responsible for the defense of its own territory.

However, the inadequacy of the deterrence provided by the U.S. in regional conflicts, such as in Ukraine, or gray zone situations, such as the South China Sea, is becoming an issue. North Korea may even have the misconception that the U.S. will not counterattack even if it intimidates or attacks Japan.

For this reason, military experts are arguing that if U.S. allies in Asia and Europe are provided with attack capability, this will constitute stronger deterrence than the U.S. alone having such capability. According to a source at the Japanese Embassy in Washington, National Security Adviser H.R. McMaster believes in this theory.

Japan’s possession of high-performance weapons such as Tomahawks will provide greater deterrence not only against North Korea, but also against China’s military provocations. China’s fierce opposition to the ROK’s deployment of THAAD illustrates its strong apprehension about its neighbors possessing advanced weapons.

American strategist Edward Luttwak told Yomiuri Shimbun: “Japan needs to possess preemptive strike capability. While missile defense is also important, it is not 100% foolproof. Possession of preemptive strike capability will enhance deterrence.”

A military source in Washington says: “The U.S. will further strengthen its alliance with Japan and the ROK in a manner that China will not be able to object to, citing North Korea’s threat as the justification.”

It appears that President Donald Trump’s desire to expand the role of U.S. allies as much as possible is also one reason the U.S. has begun to consider expanding its arms sales.

During the presidential election last year, Trump even talked about increasing Japan’s and the ROK’s share in the cost of stationing U.S. troops and permitting Japan and the ROK to acquire nuclear weapons. After his inauguration, however, he has stopped talking about these proposals that were based on misconceptions, but his basic stance of asking the allies to play a greater role is believed to remain unchanged. (Slightly abridged)