There are growing signs that something truly horrific is about to happen in Hong Kong. President Trump has essentially given China’s rulers a green light to crush the pro-democracy protests. His flippant remarks could have grave consequences.

After nearly two months of protests in the territory, Beijing’s latest actions are intensifying concerns that it may be preparing a crackdown. The White House has expressed concern about Chinese forces mustering near the border, apparently referring to 190,000 security forces who took part in recent exercises, including helicopters and armored vehicles, in the province bordering Hong Kong. On Tuesday, 12,000 anti-riot police in Shenzhen, directly adjacent to Hong Kong, took part in “anti-mob” drills clearly linked with the protests in the territory.

The same day, a regime official issued the most ominous warning yet. “Those who play with fire will perish by it,” said Yang Guang, spokesman for China’s Hong Kong and Macau Affairs office. Calling the protesters “extremely rampant and deranged,” Yang warned “a blow from the sword of law awaits them.”

The world has already seen what China is capable of.

What the Chinese Communist Party does, of course, is its responsibility, and it is the Party that will bear the responsibility if Hong Kong’s crisis ends in bloodshed. But the rest of the world, and particularly the United States, has a duty to warn against the slaughter of innocents, and to stand up for the values of free societies.

Trump had the opportunity to warn China against a heavy-handed response. He could have summoned up a joint effort with America’s allies to urge Chinese restraint. He could have warned Beijing, even if mildly. Instead, he gave the Chinese government a free pass.

Last week a reporter asked Trump whether he’s concerned about reports that the Chinese army might be preparing to intervene. The president’s response amounted to an invitation to crush the protesters. “Well, something is probably happening with Hong Kong because when you look at, you know, what’s going on, they’ve had riots for a long period of time,” he said.

The word “riots” was the first danger sign. That’s the word that delegitimizes any protest. The ones in Hong Kong started as peaceful events and only recently have turned violent, largely in response to assaults against demonstrators by baton-wielding thugs whom the police completely ignored. It was almost as if someone wanted violence to justify a crackdown.

Trump continued. “I don’t know what China’s attitude is,” he mused disingenuously. “Somebody said that at some point they’re going to want to stop that.” This would have been a good place for him to urge restraint by Beijing, to defend the people’s right to protest peacefully, to say the United States is watching closely.

Instead, he washed his hands: “But that’s between Hong Kong and that’s between China, because Hong Kong is a part of China,” he declared — a comment that dismisses Hong Kong’s autonomy, solemnly guaranteed by Beijing years ago. Then he made it clear that the United States will have nothing to say: “They [China] have to deal with that themselves. They don’t need advice.”

Trump has thoroughly relinquished any claim to moral authority by the United States. At a time when hundreds of thousands of Hong Kongers have been courageously taking to the streets to assert their rights, the demonstrative disinterest of the president of the United States is scandalous — and dangerous.

The regime’s increasingly aggressive behavior at home and abroad, its rapacious actions at sea, its construction of artificial islands in disputed areas — all of this is a threat to the United States’ allies and to international norms. If Beijing sends the military into Hong Kong, it will send a chill across the Taiwan Straits and will aggravate an already tense relationship between a rising China and a bristling America.

The people of Hong Kong, whose human rights, autonomy and liberty were supposed to be guaranteed until 2047 under the agreement that handed over the territory from the United Kingdom to China, have seen Beijing gradually intrude on their freedoms. They have been protesting for almost two months now — since just after the 30th anniversary of the Tiananmen Square massacre, that infamous day Chinese tanks crushed peaceful protesters demanding democratic reforms. They know only too well the risks they are facing.

The trigger for the protests was a proposed bill by Hong Kong’s chief executive, Carrie Lam, that would allow Hong Kong to extradite its citizens for prosecution by China, where the legal system is an extension of the ruling Communist Party. This is no fringe movement. Some 2 million people, out of a population of about 7 million, took to the streets to demand the bill’s withdrawal. Lam suspended it, but she has not fully withdrawn it.

In the meantime, the authorities’ response to the protests has infuriated the public. Protesters have increased their demands. They want Lam to resign, and they want direct elections, real democracy.

Washington should join with its democratic allies in urging restraint by Chinese authorities. Lam has just said that the city is verging on “a very dangerous situation,” and Hong Kong police are anxiously insisting they can handle the challenge, trying to keep the Chinese soldiers out.

The U.S. president, for his part, has all but rolled out a welcome mat for China’s military to march into Hong Kong.

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