Japanese Defense Minister Nobuo Kishi at a news conference in Tokyo, Sept. 16, 2020.

Japanese Defense Minister Nobuo Kishi at a news conference in Tokyo, Sept. 16, 2020.

Photo: kim kyung-hoon/Reuters

Japan’s Jun Mizutani and Mima Ito shocked reigning champion China by winning the gold medal in mixed doubles table tennis Monday. But Tokyo’s increasingly aggressive pushback against Chinese pressure on Taiwan is causing more heartburn in Beijing than lost Olympic glory.

The headline moves are all about Taiwan. On July 9, an editorial in these pages noted Deputy Prime minister Taro Aso’s remarks that a Chinese invasion of Taiwan could threaten Japan’s “survival” and that Tokyo would join Washington to defend the island in such a case. The next week Japan’s annual defense report broke with longstanding practice to highlight the importance of Taiwan to Japan. State Minister Yasuhide Nakayama, the second-ranking Defense Ministry official, told an audience at my home think tank, Hudson Institute, that the world needs to “wake up” to the threat China poses to Taiwan. Defense Minister Nobuo Kishi put it more bluntly in an interview last month: “The peace and stability of Taiwan are directly connected to Japan.”

When Mr. Kishi speaks, China listens. Younger brother of former Prime Minister Shinzo Abe, grandson of former prime minister Nobusuke Kishi, and great nephew of a third ( Eisaku Sato ), the defense minister has a history of pushing the envelope on Japan-Taiwan relations. His close and continuing contacts with the Democratic Progressive Party, the more pro-independence of the two major Taiwanese political parties, makes him a lightning rod for criticism in Beijing. Mr. Kishi’s emergence as defense minister at the center of a new Japanese consensus on Taiwan policy underlines the depth of the shift under way.

Step by step Tokyo is relentlessly discarding the pacifism that defined its foreign policy since World War II. In 2014 then-Prime Minister Abe lifted a longstanding ban on arms exports; the first major deal under the new policy came only in 2020, when Japan sold air-defense radar to the Philippines. Even as Japan’s government prepares to raise defense spending above the symbolically important threshold of 1% of gross domestic product, Tokyo is moving to promote arms sales to Malaysia, Vietnam and Indonesia.

With Japanese defense planners calling for the development and production of a new generation of sophisticated defense systems, the rapid development of a strong high-tech defense—and a defense industry to produce it—is looking more important for Japan’s future economic growth. After years of over-investment in gold-plated infrastructure projects, military spending may be the most effective form of economic stimulus that Tokyo policy makers have left.

Not only does the arms race breaking out across an increasingly insecure Asia represent a major economic opportunity. More than ever, the capabilities required to build advanced weapons are essential for civilian industry as well. State-funded military-oriented research and development will help keep Japanese companies on the technological frontier.

Declining confidence in the U.S. also drives Tokyo’s new defense policy. The last 20 years of American foreign policy didn’t impress many Japanese minds. That President George W. Bush gave the Middle East strategic priority over Asia after 9/11 discomforted many observers in Japan.

The Obama administration spoke loudly about its pivot to Asia but flubbed its response to China’s illegal construction and fortification of military bases on artificial islands in the South China Sea. The Trump administration’s shift to a stronger anti-China policy was widely welcomed in Japan, but the erratic nature of the president’s policy making and shortsighted decisions like the abandonment of the Trans-Pacific Partnership undercut Tokyo’s confidence in Washington’s reliability.

Taken together, the unpredictable lurches U.S. politics have taken in the 21st century combined with the polarization that erupted so dramatically in the Trump years leave Japan—and other allies—unsure of America’s continued will and ability to play a leading role in world affairs. All this uncertainty makes the case for building up a defense budget more compelling.

Finally, for some in Japan, the subordination of Tokyo’s foreign policy to Washington’s strategy since the 1940s feels less like a life preserver than a straitjacket. Building up Japan’s own forces offers a path to a more independent Tokyo—especially when and if Japanese public opposition to an independent nuclear deterrent gradually weakens.

For the foreseeable future, however, the Japanese-American alliance looks stronger and more consequential than ever. From Xi Jinping’s perspective, Tokyo is a strategic problem that won’t go away. An isolated Japan might be vulnerable to Chinese pressure, but its U.S. alliance makes Tokyo harder to bully. The more China throws its weight around, the more determined Japan becomes to build up its defense capabilities and deepen its links with America, Australia, India and Vietnam.

Many in Beijing seem to think that China’s rise to pre-eminence is inevitable and that their Asian neighbors will have to fall in line. Perhaps, but table tennis is not the only arena in which China’s drive for dominance is encountering an unexpectedly effective Japanese response.

Main Street: If Joe Biden intends to outcompete Beijing, surely Milton Friedman still offers a more compelling model than simply copying the government-directed approach of Xi Jinping. Images: AP/Getty Images Composite: Mark Kelly The Wall Street Journal Interactive Edition