RUTHFULLY YOURS

While the prosecution of Hong Kong’s opposition has become increasingly commonplace, the defendants in the trial beginning Tuesday are a Who’s Who of an earlier generation of activists who have been fighting for core issues like the rule of law and political participation since before the U.K. returned Hong Kong to China in 1997.

Mr. Lee is a U.K.-trained lawyer who co-founded the city’s first pro-democracy party and helped write Hong Kong’s foundational legal document, the 1990 Basic Law. Others charged include Margaret Ng, a 73-year-old barrister; Albert Ho, a 69-year-old lawyer and activist; Lee Cheuk-yan, a 64-year-old labor leader, and Leung Kwok-hung, also 64, a longtime politician and activist known as “Long Hair.”

Police arrested the group last April in coordinated early-morning raids that surprised many in the city, since those targeted were generally associated with peaceful activism and running for elected office—not the often bitter clashes between young protesters and the police. For many, the arrests signaled that authorities intended to go beyond prosecuting protesters who committed violence to crush the democracy movement itself.

The arrests came just weeks before Beijing announced its imposition of a national security law that would give mainland authorities wide latitude to enforce crimes such as sedition, terrorism and collusion with foreign powers. Today, peaceful marches are essentially banned, and even some slogans are considered illegal.

“This is a political retaliation on the part of the Chinese Communist Party,” Lee Cheuk-yan said of the trial. “Sadly now in Hong Kong, the law is being used as an instrument of political retaliation and suppression.”

Hong Kong authorities have defended the prosecutions of activists involved in unauthorized marches as upholding the rule of law and have denied prosecutions are influenced by Beijing.

At the trial Tuesday, a lead prosecutor detailed the charges of organizing and participating in an illegal assembly on Aug. 18, 2019. Though police had granted permission to hold a demonstration at a park that day, prosecutors say the event became an unauthorized march when the large crowd spilled out and organizers led it on a procession across the city. Organizers had been denied a permit for a march, and that denial had been upheld on appeal.

Two of the defendants, Au Nok-hin and Leung Yiu-chung pleaded guilty Tuesday. The rest have pleaded not guilty and will fight the charges in a trial expected to take around two weeks.

The remaining defendants don’t contest the basic facts that they helped organize or participated in the gathering, which organizers estimated drew 1.7 million people. Instead they say the charges violate a basic right to assembly and will also argue that police erred by not giving permission for a march when the expected crowd couldn’t possibly fit inside the park, defense lawyers and defendants said.

Police have also charged many of the same defendants with similar crimes related to other marches in 2019. Those trials will be heard separately. Mr. Lai, the publisher, is also facing a separate prosecution under the sweeping national security law imposed by Beijing last year to crush dissent in the territory.

A reminder of the trial’s high symbolic stakes came last month when a British barrister, David Perry, who was hired to lead the prosecution, quit the case amid criticism at home. In a televised interview, for example, U.K. Foreign Secretary Dominic Raab said Mr. Perry was handing China a “PR coup” by participating.

Mr. Perry couldn’t immediately be reached for comment. In a statement at the time, the Hong Kong government said he had “expressed concerns about such pressures and the exemption of quarantine, and indicated that the trial should proceed without him.”

Under a practice designed to bolster the credibility of Hong Kong’s courts after its return to China, overseas lawyers and judges are routinely brought in to handle local cases.