Hong Kong’s new security bill is being put to its biggest use yet

SINCE CHINA imposed a draconian security law on Hong Kong last year, protests in the city—already dampened by pandemic-related controls—have been rare. But on March 1st hundreds of people gathered outside a court to demonstrate against the largest case so far related to the security bill. They held banners calling for the release of “political prisoners” and chanted slogans that were popular during the unrest that engulfed the territory in 2019. Students at a primary school nearby stood outside their classrooms, shouting in solidarity. It was a rare act of defiance in a city that, to many residents, feels crushed.

A day earlier, 47 people had been charged for alleged misdeeds as part of the case. They included some of Hong Kong’s best-known pro-democracy activists, such as Leung Kwok-hung, a veteran campaigner commonly known as “Long Hair”; Lester Shum, a politician; Benny Tai, an academic, and Joshua Wong, whose then-teenage face became emblematic of the “Umbrella Movement” of 2014 (he is already in prison for a protest-related offence). They have been accused of crimes such as conspiracy to commit subversion by plotting to overthrow Hong Kong’s government.

The case relates to an informal primary ballot that was held last year to select pro-democracy candidates for elections to the Legislative Council. This sensible-...