The photo has been used for illustrative purposes.

For nearly four months, millions of Hong Kong citizens from all walks of life have taken to the streets to protest Beijing’s efforts to curb their freedoms.

Last week some of the youthful heroes of Hong Kong’s democracy movement came to Washington to urge Congress to support their struggle. Their arguments were convincing, and not just because they are fighting for values we share, like civil liberties and rule of law.

The Hong Kong drama has taken on a global significance that goes far beyond an internal Chinese struggle. How Beijing chooses to resolve this struggle could powerfully impact its relationship with the West.

Hong Kong’s civic freedoms were supposedly enshrined in the 1984 Sino-British declaration, an international treaty that was the basis for Britain’s return of the territory to Chinese sovereignty in 1997. The pact guaranteed Hong Kong a “high degree of autonomy” for 50 years under a “One Country, Two Systems” framework that preserved the territory’s independent judiciary and pledged to expand free elections.

Beijing has been steadily eroding those freedoms in recent years. The current protests were sparked when the city’s Beijing-backed chief executive, Carrie Lam, introduced a controversial extradition bill that would have permitted Hong Kongers to be sent for trial in mainland China’s courts, which are subject to Communist Party control.

“Today, we are approaching dangerously close to “One Country, One System,” the 22-year-old, bespectacled, Joshua Wong testified before the Congressional-Executive Commission on China. Wong was a teen-aged leader of the 2014 Umbrella Movement that protested Beijing’s escalating curbs on election freedoms. When I interviewed him in 2016, he conceded that the odds of preserving Hong Kong democracy resembled David’s against Goliath, but said, “We are trying to create a miracle.”

Clearly Beijing is wary of a military crackdown that might resemble the 1989 massacre in Tiananmen Square, and Lam recently withdrew the extradition bill. However, demonstrators now insist they won’t stop before election freedoms are expanded and jailed protesters released. Wong cautioned: “Sending in the tanks remains irrational but not impossible.”

Here is where the Hong Kong issue becomes far larger than the fate of its 7.5 million people. If Beijing cannot tolerate the “one country, two systems” model within its territory, to which it is committed by treaty, what does that portend for its future behavior towards small democracies nearby? What would that mean for the political future of Taiwan, a U.S. ally, which Beijing considers to be a renegade province?

“If Hong Kong falls, it would easily become the springboard for ... China to push its rules and priorities overseas,” argued singer and democracy activist Denise Ho. She has been blacklisted as a performer in China for her political stance.

One world, two models, with China promoting the authoritarian model as the winner?

But there is yet another reason for Congress — and Americans — to focus on developments in Hong Kong. US law gives special economic benefits to Hong Kong — treating it as a separate customs territory from mainland China, so long as Hong Kong remains “sufficiently autonomous.”

So Congress should pass the Hong Kong Human Rights and Democracy Act, which would require the Secretary of State to certify annually that the territory met that standard. As Wong put it, “Beijing shouldn’t have it both ways, reaping all the economic benefits of Hong Kong’s standing in the world while eradicating our freedoms.”

And if President Trump were paying attention — rather than sloughing off the Hong Kong upheaval as “a very tough situation” — he would be quietly messaging Xi Jinping that it was in Beijing’s interest for the Hong Kong crisis to be peacefully resolved.

After all, well over half of all nonportfolio investment coming to and from China to the rest of the world passes through Hong Kong in one form or another, according to former US Consul General in Hong Kong, Kurt Tong. “Why would that be? It’s because of the legal structure and the reliability of the Hong Kong courts and Hong Kong law,” he said recently, at the Center for Strategic and International Studies in Washington. That’s why there’s 1,400 US companies operating there.

In other words, support for Hong Kong’s democracy activists is good for US interests, US values, and even for Beijing, if it grasped the message. “Historians will celebrate the United States Congress for having stood on the side of Hong Kongers,” Joshua Wong promised.

If Congress and Trump do the right thing — and soon.