While America’s attention has been focused on the North Korea crisis, diverted occasionally to developments in the South China Sea, another volatile East Asia confrontation has reemerged. China is adopting a growing number of measures to intimidate Taiwan, including emphasizing that any hopes the Taiwanese people and government have to perpetuate the island’s de facto independence are unrealistic and unacceptable. Hostile actions include a renewed effort to cajole and bribe the small number of nations that still maintain diplomatic relations with Taipei to switch ties to Beijing, extremely explicit warnings that China will use force if necessary to prevent any “separatist” moves by Taiwan, and a sharp increase in the number and scope of military exercises in the Taiwan Strait and other nearby areas.

The military maneuvers are especially unsettling. According to Taiwanese media accounts, China has conducted 16 military drills around Taiwan in 2017, compared to just eight in 2016 and even fewer during the years between 2008 and 2016. Chinese military aircraft engaged in exercises near Taiwan’s northern coast in December. Beijing’s naval and air power war games culminated in January 2018, when a flotilla including China’s only aircraft carrier sailed through the Strait. A senior Chinese official, Liu Junchuan, the liaison head of China’s Taiwan Affairs Office, boasted that “the contrast in power across the Taiwan Strait will become wider and wider, and we will have a full, overwhelming strategic advantage over Taiwan.”

Understandably, the Taiwanese are increasingly worried about Beijing’s saber rattling. Officials in Taipei assert that the burgeoning military activity poses an “enormous threat” to Taiwan’s security. The Chinese government responded by telling the Taiwanese that they needed to get used to air force and naval units encircling the island, because those activities were not going to cease.

The mounting tensions between Taipei and Beijing should be attracting more notice. Beijing’s increased assertiveness, if not outright belligerence, is more than a matter of abstract concern to the United States. The 1979 Taiwan Relations Act (TRA), which Congress adopted when Jimmy Carter’s administration formally recognized the People’s Republic of China (PRC) and downgraded Washington’s relations with Taipei to informal economic and cultural ties, specified two security concerns. The United States pledged to regard any PRC effort to coerce Taiwan as a grave threat to the peace of East Asia. It also promised to sell “defense articles and defense services in such quantity as may be necessary to enable Taiwan to maintain a sufficient self-defense capability.”

Although the TRA’s commitments are not the same as a U.S. treaty obligation to use military force to defend the island, they are far from trivial. If an armed conflict erupted between the PRC and Taiwan, it is almost certain that the United States would be caught up in the fighting.

Tensions between Beijing and Taiwan have flared before, but they seem especially ominous this time. Chinese officials are hypersensitive about any Taiwanese trappings of independence, even though the island has never been under the PRC’s control. Australian scholar Andrew Tan aptly summarizes Beijing’s attitude: “For China, Taiwan represents unfinished business from the Chinese civil war and an emotionally charged nationalist issue that far outranks tensions in North Korea, the Senkaku Islands and the South China Sea. For a rising great power that is increasingly confident, assertive and nationalistic, the reunification of Taiwan with the mainland is its top, non-negotiable national priority.” Indeed, the PRC passed its Anti-Secession Law in 2005, emphasizing that China would use force if necessary to prevent any move by Taiwan toward formal independence.

Bilateral tensions receded in 2008 when Taiwanese voters elected Kuomintang Party (KMT) leader Ma Ying-jeou as president. Ma pursued a policy of détente and worked assiduously to increase economic ties with the mainland. Bilateral trade exploded and large numbers of Chinese tourists came to the island for the first time, facilitated by the establishment of commercial airline routes.

U.S. officials breathed a sigh of relief, and Chinese leaders exuded confidence that the web of economic ties would cause pro-independence sentiment in Taiwan to recede and eventually lead to the island’s reunification with the mainland. Instead, there was a backlash. Taiwanese sentiment for reunification was—and remains—exceedingly low. Growing worries that the trade links to the PRC were undermining Taiwan’s autonomy, combined with mounting public anger at the KMT’s pervasive corruption, led to the so-called Sunflower Movement of students and civic leaders, which erupted into widespread protests and demonstrations against Ma’s government in 2014 and 2015.

Elections in January 2016 produced a landslide victory for the pro-independence Democratic Progressive Party (DPP). Not only did the party’s nominee, Tsai Ing-wen, capture the presidency, but for the first time in history the DPP won control of the national legislature. Chinese leaders were both shocked and furious.

Since that election, cross-strait relations have deteriorated inexorably. Warnings from Beijing to Tsai and the Taiwanese public came early and often. Zhang Zhijun, the head of the Taiwan Affairs Office, put it bluntly to a visiting Taiwanese business delegation in May 2016, just weeks after Tsai took office: “There is no future in Taiwan independence, and this cannot become an option for Taiwan’s future. This is the conclusion of history.” Noting that “some people say you must pay attention to broad public opinion in Taiwan,” Zhang scorned such reasoning. Instead, “Taiwan society ought to understand and attach great importance to the feelings of the 1.37 billion residents of the mainland.”

Tsai took a number of actions that incensed Beijing. She launched a dialogue regarding mutual security concerns with China’s regional arch-adversary, Japan. In early June 2016, Taiwan’s parliament for the first time held a commemorative ceremony marking the victims of the 1989 Tiananmen Square massacre. That ceremony was an ostentatious poke in the eye to Beijing authorities. Then there was the famous (or infamous) telephone call that Tsai initiated with then-president-elect Donald Trump. To Chinese leaders, her action was a blatant attempt to induce the new U.S. leader to treat Taiwan as a fully independent country.

Beijing promptly renewed its efforts to lure away Taiwan’s handful of remaining allies—a campaign that it had de-emphasized when Ma was president. In late December 2016, Sao Tome broke relations with Taipei, and in June 2017, Panama, perhaps Taipei’s largest and most significant diplomatic partner, did the same. In addition to playing diplomatic hardball, Beijing drastically stepped up its military pressure.

U.S. leaders need to reconsider whether the implied defense commitment to Taiwan serves America’s best interests or now poses an unacceptable risk. It was one thing to shield the island when Beijing had no ability to repel an American military intervention, and prudent Chinese leaders, knowing that, refrained from launching an attack against Taiwan. Thus was it low risk for the United States to sail an aircraft carrier battle group through the Taiwan Strait in 1996 during an earlier crisis.

But the situation has changed dramatically since then. Beijing has invested hundreds of billions of dollars in military modernization efforts, especially to develop anti-ship missiles and other “access denial” systems. Today, a U.S. intervention to save Taiwan would still likely succeed, but it would be far more perilous and come at a much greater cost in blood and treasure. In another few years, prospects for success will be even more uncertain.

The United States needs to reassess the TRA and separate the obligations it contains. Washington should continue to sell arms to Taiwan, despite Beijing’s predictable, chronic protests. Such sales give the Taiwanese the option to continue resisting the PRC’s demands for steps towards reunification, if they wish to incur the attendant risk. However, U.S. leaders should also make it clear that Taiwan is on its own, and alter the TRA’s language to remove any implied defense commitment. As fond as we might be of a vibrant, democratic Taiwan, risking a catastrophic war with China is far too great a price to pay to preserve the island’s de facto independence.

Ted Galen Carpenter, a senior fellow in defense and foreign policy studies at the Cato Institute and contributing editor at The American Conservative, is the author of 10 books and more than 700 articles on international affairs.