HONG KONG — A Hong Kong court was hearing the final arguments Monday in the national security trial for two organizers of the large vigils remembering the 1989 Tiananmen Square crackdown.

Hong Kong for decades was the only place in China where a large-scale public commemoration of the crackdown was held. The vigils were banned in 2020, and the two former organizers were charged in 2021 with inciting subversion under a Beijing-imposed national security law that has virtually stifled the city’s pro-democracy movement.

Chow Hang-tung and Lee Cheuk-yan, two former leaders of the Hong Kong Alliance in Support of Patriotic Democratic Movements of China, have pleaded not guilty. If convicted, they could face up to 10 years in prison.

Observers say their prosecution reflected the city’s decline in Western-style civil liberties, which Beijing promised to maintain for 50 years when the former British colony returned to its rule in 1997. The governments of Beijing and Hong Kong insist that the security law is necessary for the city’s stability.

During the trial, the prosecution focused on “ending one-party rule,” one of the alliance’s core demands, arguing that their advocacy was about inciting others to use unlawful means to overthrow the leadership of China’s ruling Communist Party. It alleged the defendants were not advocating for amending the constitution.

On Monday, prosecutor Ned Lai said freedoms of speech, assembly and association are not absolute rights, accusing Lee and Chow of attempting to blur the focus with human rights arguments.

“The freedoms of speech, association and assembly mentioned by D2 and D4 are not ‘trump cards’ that can override the law,” Lai said, referring to Lee and Chow by their defendant numbers.

Lawyer Erik Shum, who represented Lee, said the prosecution still could not present evidence to prove what exactly the alliance had asked residents to do, even when the trial neared its end.

The hearing will continue in the afternoon.

In previous hearings, Lee denied that “ending one-party rule” means ending the Communist Party’s leadership. He argued that it actually means moving toward democracy, letting the people decide who leads them, and that the Communist Party should not enforce “dictatorship.”

Chow, a barrister who defended herself, had argued that her past writing was not about inciting action or hatred and was instead intended to foster Hong Kongers’ understanding of mainland China, where many Chinese also hoped to pursue democracy.

Their co-defendant, Albert Ho, entered a guilty plea when the trial began in January. Pleading guilty typically could result in a sentence reduction.

The trial, initially scheduled to last 75 days, is expected to end earlier. But the judges have not yet indicated when a verdict could be delivered.

Amnesty International’s Deputy Regional Director Sarah Brooks said in a statement that the prosecutors’ case relied on “vague, overly broad and arbitrary definitions of ‘subversion,’” calling on the charges against Chow and Lee to be dropped.

Tens of thousands of people attended Hong Kong’s annual Tiananmen vigils until authorities banned it in 2020, citing the COVID-19 pandemic.

After COVID-19 restrictions were lifted, the former vigil site was occupied instead by a carnival organized by pro-Beijing groups. Some people who tried to commemorate the event near the site on June 4, the crackdown’s anniversary, were detained.