HONG KONG--Verdicts in Hong Kong’s largest national security case to date, involving some of the city’s best-known pro-democracy activists, will be delivered on Thursday, more than three years after the defendants’ arrest.

In 2021, 47 pro-democracy activists were charged with conspiracy to commit subversion under the sweeping, Beijing-imposed national security law for their involvement in an unofficial primary election. The mass prosecution crushed the city’s once-thriving political activism and dimmed hopes of a more democratic Hong Kong.

Sixteen of the 47 defendants are expecting to hear their fate on Thursday and Friday and could face up to life in prison if convicted.

Critics argue the law has drastically eroded the freedoms that are vital to maintaining the city’s status as a global financial hub. “It is a trial of the pro-democracy movement in Hong Kong,” said Eric Lai, a research fellow at Georgetown Center for Asian Law.

What to know about the security case:

Many of the city’s most prominent democracy advocates are among the 47 activists, whose ages range from their 20s to 60s.

It includes legal scholar Benny Tai, about a dozen former pro-democracy lawmakers such as Claudia Mo and Alvin Yeung, and activists such as Joshua Wong and Lester Shum. Many have been detained without bail for more than three years.

Sixteen of the defendants — including former lawmakers Leung Kwok-hung and Raymond Chan and journalist-turned-activist Gwyneth Ho — began their trial in February 2023 after pleading not guilty. The court has scheduled two days of hearings for their verdicts.

Thirty-one others, including Tai, Mo, Yeung, Wong and Shum, have pleaded guilty. They have a better chance of shorter jail terms and will be sentenced at a later date.

Riding on a huge wave of anti-government protests in 2019, the pro-democracy camp was likely to make gains in the 2020 legislative election. The primary was meant to shortlist pro-democracy candidates who would then run in the official election.

The camp hoped to secure a majority in the legislature to press for protesters’ demands, which included greater police accountability and democratic elections for the city’s leaders.

In March 2020, Tai, a key organizer of the primary, said that obtaining a controlling majority in the legislature, which is typically dominated by the pro-Beijing camp, could be “a constitutional weapon with great destructive power.”

Ahead of the election, the government warned that the vote might violate the national security law. Despite this, the July 2020 pro-democracy primary was held and attracted an unexpectedly high turnout of 610,000 voters — over 13% of the city’s registered electorate.

Beijing quickly criticized the vote as a challenge to the national security law, and in January 2021, over 50 activists were arrested under the law and 47 of them were later charged.

The prosecutors alleged the defendants had agreed to indiscriminately veto government budgets to compel the city leader to dissolve the legislature and force the leader to step down.

The prosecution said the purpose of the alleged conspiracy was to subvert state power, pointing to how Tai described securing the majority as a “constitutional weapon” and referred to newspaper articles he wrote about “mutual destruction.” In one of the articles, Tai suggested that repeatedly blocking government budgets could grind governmental functions to a halt, they said.

The prosecutors said 33 of the activists had endorsed a joint declaration that pledged they would use their legislative powers, including vetoing budgets, to compel the city leader to address the protesters’ demands.

Four of the defendants who pleaded guilty also testified for the prosecution.

The defense argued that “unlawful means” to subvert state power should entail physical coercion or criminal conduct. One of the lawyers, Randy Shek, said his clients were only seeking to push for democratic elections for residents to pick the city’s leader and lawmakers. Shek said they were relying on a constitutional mechanism to push for changes.

“What they did was simply seeking (to) hold power to account, and that could not be subversion,” he said.

Prosecutor Jonathan Man argued that unlawful means didn’t necessarily imply physical violence. He said that in the 21st century, when it’s convenient to communicate with the public via social media, it’s also easy to manipulate those channels “to endanger national security.”

Experts say the verdict is a litmus test of how the national security law will be used against political opponents and activist activities.

Since the law was enacted, the Hong Kong government has insisted the city’s judicial independence is being protected. But Thomas Kellogg, executive director of Georgetown University’s Center for Asian Law, said the verdict would show that the security law, and the law more generally, is being used to crack down on Hong Kong’s political opposition.

“Hong Kong’s rule of law is simply not nearly as robust as it once was, and I worry that legal protections will continue to deteriorate,” he said.

The verdict will likely also show whether non-violent political participation — in this case, holding a public vote — is deemed a national security crime, said Lai, the research fellow with the same center. He added that another key issue the court would rule on is the legislative council’s veto power over the budget.

“It is important to see whether the court would qualify the exercise of constitutional power by the legislature,” he said.

After the verdict, the court is expected to schedule hearings for any convicted defendant to ask for a more lenient sentence.

Following that, the judges, who were approved by the government to oversee the case, will deliver sentences to the convicted people.

Kellogg said several of the top activists among the 47 accused could receive sentences of 10 years or more.

“Many among the 47 have missed birthdays and graduations of sons and daughters, and also even the deaths of elderly family members. It’s important not to overlook the very real costs involved here,” he said.