Defense Minister Itsunori Onodera suggested that the Self-Defense Forces could take part in a war between the United States and North Korea if Pyongyang attacks the U.S. island territory of Guam.

At a Lower House Security Committee meeting on Aug. 10, Onodera said an attack against Guam, a U.S. military hub, would weaken the power of the United States, thereby putting Japan’s existence in danger.

In such a case, Japan could exercise its right to collective self-defense, which enables the country to help the United States militarily, he said.

“Japan has a role as a shield. The United States has a role of heightening deterrence with its striking power. We cannot rule out the possibility that a U.S. loss of striking power would correspond to a situation that endangers Japan’s existence,” Onodera said in response to questions from Yuichi Goto, a lawmaker of the main opposition Democratic Party.

“If the situation meets the three conditions to use force in exercising the right to collective self-defense, we will be able to do so,” Onodera said.

It is extremely rare for a Japanese defense minister to refer to the possibility of entering a war, even in general terms.

North Korea on Aug. 9 warned that it is considering launching four ballistic missiles toward waters off Guam.

Masahiro Sakata, former director-general of the Cabinet Legislation Bureau, said Onodera’s remarks correspond to the expanded interpretation of a “situation that will endanger Japan’s existence as a country.”

However, in order for Japan to recognize such a situation, the United States must first exercise the right to individual self-defense after it was attacked.

“If the United States has not exercised the right to individual self-defense yet, Japan cannot recognize the situation as one that endangers its existence,” Sakata said.

Concerns have been raised that the government’s broader interpretation of such a situation will make it easier for SDF to take part in wars abroad.

“The situation that endangers Japan’s existence must be interpreted strictly,” Sakata said. “Unless the government does so, the SDF will easily participate in overseas wars.”

There are doubts about whether Japan has sufficient capabilities to intercept North Korean missiles that are flying toward waters off Guam.

A senior official of the Defense Ministry said it is technically difficult to shoot down such missiles, which would fly over the Chugoku and Shikoku regions in western Japan, with SM3 interceptor missiles loaded on Aegis ships.

Japan and the United States are currently jointly developing “SM3 Block 2A” missiles that have longer flying distances and higher accuracy than the SM3 missiles.

(This article was written by Ryo Aibara and Koji Sonoda.)