The images from Hong Kong Polytechnic University are dramatic: desperate students trying to escape arrest at the hands of an increasingly aggressive police force — responding, they say, to increasingly violent protesters.

Other memorable images from the five-month mass protest movement include millions marching peacefully against a since-scrapped proposal that would have allowed extradition of Hong Kong residents to the often-unjust Chinese justice system. While that proposal has since been withdrawn, other demands remain, which is one factor behind the violence that threatens to end the initial broad backing for the largely leaderless movement.

The searing images on campus can be put into a broader context of Beijing’s slow siege on Hong Kong’s distinctly different system itself. Indeed, the depth and breadth of the protests suggests a justifiable fear that Beijing is not honoring the “one country, two systems” semi-autonomy that was promised when the United Kingdom handed over its former colony to China in 1997.

“It’s a struggle over what is the proper meaning of the rule of law,” Jerome A. Cohen, a senior fellow for Asia Studies at the Council on Foreign Relations, told an editorial writer. “Beijing says the rule of law is: You have to do whatever the government says you have to do, however unreasonable, however restrictive on fundamental freedoms and human rights.”

Conversely, Cohen added, “The opposition says the rule of law is that there’s limits on government, and those limits are imposed by the constitutional document, which is supposed to be protective of human rights and freedom of expression. So, this is the real meaning of the struggle of Hong Kong — that’s why the world is being alerted to its significance.”

Washington seems to sense the relevance, too.

On Monday, Secretary of State Mike Pompeo repeated a call for restraint and rightly said that the Hong Kong government “bears primary responsibility” for the situation and that the Chinese Communist Party “must honor its promises to the Hong Kong people.” In the U.S., Congress should expedite a stalled Hong Kong Human Rights and Democracy Act. And for his part, President Donald Trump should not tie progress on his ongoing trade dispute with China to staying silent on Hong Kong, or the mass detention of Muslims in Western China, a program that was detailed in a chilling New York Times exposé on Sunday.

Because Beijing “has the power, the military, the police and the will as demonstrated by recent speeches by [Chinese President] Xi Jinping,” Cohen believes that in the immediate term “Beijing is going to win this struggle.”

But he then asks, “The question is, ‘What is the impact of this? Can the world’s reaction and the reaction of people in Hong Kong and even the mainland have a moderating impact over time, and can Xi Jinping endure in the current circumstances?’ ”

The free world should resist Beijing on Hong Kong and, as the leader of those nations, the U.S. government should be bold in speaking out.