Remember, these are the cops that have supposedly sworn to uphold the constitution.
I've said it before and I'll say it again. When faced with obeying an unconstitutional order and trampling on the rights of citizens or losing their job the overwhelming majority of police will default to their paycheck.
What would things have been like if every Security operative, when he went out at night to make an arrest, had been uncertain whether he would return alive and had to say good-bye to his family? Or if, during periods of mass arrests, as for example in Leningrad, when they arrested a quarter of the entire city, people had not simply sat there in their lairs, paling with terror at every bang of the downstairs door and at every step on the staircase, but had understood they had nothing left to lose and had boldly set up in the downstairs hall an ambush of half a dozen people with axes, hammers, polkers, or whatever else was at hand?
Part I The Prison Industry, Ch. 1 "Arrest" (p13, The Gulag Archipelago, Collins 1974)