President Trump has had a superb 24 hours on his strongest (and America's most important) foreign policy issue: China.

First, Trump tweeted his impatience with Chinese prevarication in ongoing trade talks. And the president pledged to impose new tariffs if progress is not made by Friday.

Then, on Monday, two U.S. Navy destroyers traveled within 12 miles of two reefs in the Spratly Islands chain of the South China Sea — reefs that China claims as its own, although illegitimately.

China's reaction to both acts was one of fury. One state newspaper described Trump's tweet as blackmail. The Chinese Foreign Ministry claimed that "the trespass of U.S. warships is a violation of China's sovereignty. It undermines peace, security and good order in the relevant waters. China deplores and firmly opposes such moves."

Trump should revel in Beijing's anger, because his policy is right on the mark here. Chinese President Xi Jinping intends to destroy the U.S.-led international system of fair commerce under the democratic rule of law. He aims to replace it with one of intellectual theft and feudal mercantilism. China is playing games in the trade negotiations to protect that agenda. But Trump's tariffs and other economic actions challenge Xi by jabbing at his unelected regime's economic vulnerability.

Xi's claims to the Spratly Island chain, meanwhile, are totally insane. Those international waters are 700 miles away from the closest bit of actual Chinese territory, Hainan Island. But were Trump to accept China's dominion, a 1930s-style Japanese subjugation of the Pacific Rim would follow. And that subjugation would come with Xi's control over the more than $3.3 trillion in trade that flows through the South China Sea each year. The U.S. Navy must be adequately supplied, but Trump is standing up for global order. It's a welcome change: President Barack Obama appeased Xi to America's cost.

Note one final thing here: there was a unique American beauty to this latest naval patrol. One of the destroyers was the USS Chung-Hoon. That ship is named for a great American of part-Chinese descent, who fought to keep the Pacific Ocean free 70 years ago. Now, under his name and example, Americans continue to stand watch for the free world. China should be wary.