During a debate in the Upper House, on 5 July 2021, Japanese Deputy Prime Minister Taro Aso was quoted as saying: "If a major incident occurs in Taiwan, it’s not at all unusual to consider it an existential threat [to Japan]," "In such a case, Japan and the United States will have to work together to defend Taiwan."

The legislation that was pushed through in 2015 to amend the Constitution, allows Japan’s military to mobilize only if its survival is threatened.

The People’s Republic of China immediately reacted, accusing Tokyo of interfering in her internal affairs. Last month, when the G7 pledged its military support to Taiwan, China responded by sending 28 fighter planes over the island.

The Pentagon has refrained from any comments considering that Taiwan’s reintegration as part of a single China would put an end to the civil war from the early twentieth century.

According to the Financial Times, last week the US and Japan conducted joint military exercises and war games as possible preparation for conflict over Taiwan. They were reportedly organized as part of a Pentagon plan developed in 2020, that is, during Donald Trump’s mandate.