The gathering of defense chiefs from 25 countries at Singapore’s Shangri-La Hotel did more to deepen, sharpen and define insurmountable obstacles than to head off the rising confrontation between American and Communist Chinese forces in Asia.

As if to dramatize how deep is the standoff, the Chinese provided a prime example of the tensions that now are raising concerns about the dangers of war breaking out in the region’s disputed skies and waters.

A day after the American defense secretary, General Lloyd Austin, had warned Beijing against “coercion and bullying,” a Chinese warship sailed perilously near an American guided missile destroyer and a Canadian frigate in the Taiwan Straits between the Chinese mainland and the independent island democracy of Taiwan.

Could the incident have been staged deliberately by the Chinese, who clearly were not impressed by General Austin’s vision of a “free, open, and secure Indo-Pacific within a world of rules and rights”?

There’s no telling if the episode was China’s answer to America’s commitment to the defense of Taiwan and freedom of the seas, but China’s defense minister, Li Shangfu, in his third month in the post, could not have asked for a better pretext for berating the Americans for “actions against other people’s territories.”

In the Taiwan Straits the Chinese ship cut just 150 yards in front of the American destroyer, leaving no doubt the Chinese will try to intimidate the Americans every chance they get off Taiwan and in the South China Sea. The Chinese claim both these international waterways are theirs.

Generals Li and Austin both managed to smile and shake hands without attempting to hash out the bitter differences that appear to be going from bad to worse.

It was probably just as well they didn’t sit down for a private chat before leaving the weekend confab. While the two former generals would no doubt have tried to be polite, they likely would not have gotten anywhere in compelling either to back down from strongly stated positions. If nothing else, there was always the possibility of raised voices and fist-pounding.

A former Chinese ambassador to Washington, Cui Tiankai, explained China’s position in an interview with the Straits Times, the main Singapore newspaper. (The “Straits” in that title refer to the Straits of Malacca between Malaysia and Indonesia plus the straits between Singapore and Indonesia.)

“Some people are talking about our ships apparently getting too close to their ships and their plane,” Mr. Cui was quoted as saying, “But the real question is, why are they coming all the way across the ocean, to our doorstep? They’re getting too close to our territories, to our territorial waters. It’s certainly a disrespect of other countries’ sovereignty and territorial integrity.”

Mr. Cui, whose tenure from 2013 to 2021 makes him China’s longest-serving ambassador to Washington, did his best to promote good-will while standing behind the policies of his government.

Having sat through meetings as ambassador between China’s President Xi and Presidents Obama, Trump, and Biden, Mr. Cui quoted Mr. Xi as saying “we want to base our relations with the United States on the principles of mutual respect, peaceful coexistence and win-win cooperation.”

But, he said, “We’re still waiting for a positive and constructive response.”

General Li did not appear positive, however, about cooperation between Chinese and American ships and planes. It was one thing to engage in “innocent passage,” he said, but quite another to use “freedom of navigation” and “innocent passage” as a pretext to “exercise hegemony of navigation.”

He coupled his lecture with a warning of storm clouds on the horizon:  “We must not allow such tragic history to repeat itself,”  a grim reminder of the war that engulfed the region after the Japanese bombed Pearl Harbor in December 1941.