Protesters are beaten and locked up almost immediately, huge "pens" are made to coral them like animals, and recently the new tactic is to make "safe zones" where people are not even allowed near the events anymore.
If there was even a hint of weapons being used, our police are heavily militarized now and would not hesitate to shoot someone even holding a smartphone if they thought they could get away with it. Virtually no police are prosecuted in any given year for shooting unarmed people in the USA, happens every week.
However what you have in the Ukraine is something I am jealous of, people actually care.