Not that slowly and very steadily, the Chinese government is making political inroads in Hong Kong.

Over the past year or so, it maneuvered to expel pro-democracy legislators from Hong Kong’s lawmaking body, sidelined a popular candidate for the city’s top post to give the job to a proven hard-liner and got local high schools to beam to their students an ideologue’s speech about the Chinese Communist Party’s latest national congress. Now it is demanding that the Hong Kong legislature, known as LegCo, pass a law, modeled after one in force on the mainland, to enforce respect for the Chinese national anthem.

Worse, under the guise of an innocuous train-transit project, the Chinese government is trying to exercise a form of extraterritoriality in the very heart of the city — an apparent dry run for eventually passing security laws limiting political freedoms in Hong Kong.

Starting in late 2018, high-speed trains will connect Hong Kong to Guangzhou, a megacity on the mainland, and there is a plan to place inside the terminus in Hong Kong an immigration and customs checkpoint that would include Chinese security personnel enforcing Chinese law, with search-and-arrest authority. The proposed arrangement is known in Chinese as “one location, two checkpoints” — an ominous play on “one country, two systems,” the principle supposed to guarantee a measure of self-rule for Hong Kong.

Some supporters of this 1L2C scheme compare it, speciously, to the customs preclearance procedure that the United States government has set up in several Canadian airports. They also praise the new setup’s efficiency, arguing that, at least on some routes, one hour or more could be shaved off a trip that currently takes two.