Chinese Navy sailors patrol the disputed Spratly Islands on February 9, 2016. The sign reads Spratly “is our national land, sacred and inviolable.”China Stringer Network / Reuters

If China’s intentions in the South China Sea weren’t quite clear, this month should have removed doubt. News reports said China had installed anti-ship cruise missiles and surface-to-air missile systems on the disputed Spratly Islands—and had also built 400 buildings that can accommodate its military forces on a reef there. Then, China said it had landed bombers on manmade islands in disputed waters in preparation for what it called “the battle for the South China Sea.” It then emerged that a bomber landed on an island in the disputed Paracels.

Taken individually, China’s actions might indicate a geopolitical game of chicken wherein Beijing tests its neighbors over territory they too claim to see the limits of their tolerance. But taken together, it’s clear China is showcasing its military strength over all area it claims as its own—international opinion be damned. And why not? Previous actions have drawn little more than regional hand-wringing and disapproval from the U.S. But this time was different: In response to these actions, the United States, which is already embroiled in a trade dispute with China, decided to disinvite it from a biennial regional military exercise that the Chinese military participated in for the first time in 2016.

The Defense Department said Wednesday it was rescinding China’s invitation to participate in the Rim of the Pacific exercise in Hawaii because of what it called a “violation of the promise” not to militarize the Spratly Islands.

“The United States is committed to a free and open Indo-Pacific. China’s continued militarization of disputed features in the South China Sea only serve to raise tensions and destabilize the region,” Lieutenant Colonel Christopher Logan, a Pentagon spokesman, said in a statement. “As an initial response to China’s continued militarization of the South China Sea we have disinvited the PLA Navy from the 2018 Rim of the Pacific (RIMPAC) Exercise. China’s behavior is inconsistent with the principles and purposes of the RIMPAC exercise.”

Logan said the U.S. had evidence China has deployed anti-ship missiles, surface-to-air missile systems, and electronic jammers in the disputed Spratly Islands, the chain in the South China Sea that is claimed by China as well as Malaysia, Philippines, and Vietnam. The spokesman also cited China’s recent landing of a bomber at Woody Island, a part of the Paracels, which is also claimed by Vietnam, as a cause of concern.

“We believe these recent deployments and the continued militarization of these features is a violation of the promise that President Xi made to the United States and the World not to militarize the Spratly Islands,” Logan added.

The Defense Department’s decision Wednesday coincided with the visit to Washington by Wang Yi, who is China’s highest-ranked diplomat. Wang met with U.S. Secretary of State Mike Pompeo reportedly to discuss North Korea, but the two men also discussed the Pentagon’s decision. Pompeo said he would let the Defense Department “to talk about that. Only to say that we have expressed consistent concern about militarization of the South China Sea.”

Wang had more to say; he called the disinvitation a “very unconstructive move, nonconstructive move. It’s also a decision that’s taken lightly. It’s unhelpful to mutual understanding between China and the U.S. We hope the U.S. will change such a negative mindset.”

“China is only building civilian and some necessary defense facilities on our own islands” in the South China Sea, he said. “That is the right to self-defense and preservation of every sovereign state. It is a normal deployment and has nothing to do with militarization, just like the U.S. has military presence in Hawaii, in Guam. And China’s deployment is at a much smaller scale than the U.S. It’s just out of necessary defense purposes. We don’t hope to see any exaggeration or hype-up of this matter.”

The Pentagon’s decision also came against the backdrop of the trade dispute with China. Talks between the two countries ended recently: The U.S. said it would delay the tariffs on Chinese products entering the country. China’s commitment were vaguer—though it did promise to lower the the trade deficit with the U.S. by an unnamed amount.

The Trump administration finds itself in a curious place with China, which is clearly emerging as a counterweight to the U.S. in many parts of the world—including in South America. Its large loans on easy (critics would say predator) terms for massive infrastructure projects across the world have made many smaller countries that have a difficult time securing funds from U.S.-led multilateral institutions, either because of their poor creditworthiness or poor governance, turn to Beijing, which is less interested in the latter. The two countries are also regional rivals in Asia, where the U.S. is still a dominant military power—though one that looks increasingly reluctant to use its might overseas. At the same time, the U.S. needs China’s help to fix its most vexing foreign-policy problem at the moment: North Korea. Beijing has unique—if limited—influence in Pyongyang, but ultimately could emerge pivotal if talks were to occur between President Trump and Kim Jong Un, the North Korean leader, next month in Singapore.

Which brings us back to the dispute over the South China Sea. China, arguably the most powerful Asian military power, has in recent years built facilities and military bases to bolster its claims over the waters. The U.S. and other nations want the South China Sea, which is an important trade route, to remain international waters, so shipping vessels continue to enjoy freedom of navigation. Tensions involving China and its neighbors over the waters and the islands in them have persisted for decades, but have spiked in recent years.

The biennial Rim of the Pacific exercise, which will run from June 27 to August 2,  brings together forces from Australia, Canada, New Zealand, the U.K., and several other countries. China first participated in the exercise in 2016 (it was first invited in 2014). Yet that participation always occurred in a context of tension with its neighbors. Ash Carter, the U.S. defense secretary at the time, acknowledged regional concern about China’s intentions, but said he hoped participation in the Rim of the Pacific exercise would give Beijing the opportunity to “try to be part of the system of cooperative nations that have made, as I said, the Asian miracle possible.”

China is hardly the only country to be disinvited from Rim of the Pacific exercise. In 2016, Russia’s invitation was rescinded for its annexation of Crimea. But as USNI noted, the “Russian Navy sent a destroyer to follow USS America (LHA-6) and a spy ship to monitor the exercise.”

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