Indeed, American and Japanese alliance minders have been here before. In 2009, the Democratic Party of Japan interrupted the long reign of the conservative LDP and installed a center-left prime minister. Yukio Hatoyama had campaigned on a platform that alarmed security officials and analysts in both Washington and Tokyo. For example, he called for "fraternal" cooperation with Japan's Asian neighbors, including China, and pledged to reduce the U.S. military footprint in Okinawa, home to more than 30 American bases. After less than nine months in office, Hatoyama was forced to step down.

But Shigeru Ishiba is no Yukio Hatoyama. Although he wants to rebalance U.S.-Japan ties, and also favors greater engagement with Beijing, he is actually quite conservative and hawkish, even on China. He is a member of Nippon Kaigi, the ultra-nationalist group that believes Japan was not a villain in World War II; he favors greater defense spending; and he openly backs Taiwan. Ishiba riled Beijing in August by leading a group of lawmakers to Taipei, where he drew parallels between Russia's invasion of Ukraine and security threats in the Taiwan Straits. He hinted that Japan should help deter any Chinese invasion.