Sam Cheung, a young activist and a participant in an unofficial primary election last summer, was charged after reporting to a local police station, dressed in a black mask and accompanied by his wife. “Hong Kongers have a really tough time these days,” he told reporters before entering the station. “I hope everyone won’t give up on Hong Kong ... (and) fight on.” Cheung was arrested in a dawn raid along with more than 50 other democrats on Jan. 6 in the largest national security operation since the law’s passage last June. They were accused of organising and participating in...