Remember how this used to happen with the tea partiers?

http://www.denverpost.com/breakingnews/ci_19223274

In the most violent Saturday in more than a month of Occupy Denver demonstrations and marches, Denver police fired mace and pepper balls at a crowd of protesters in Civic Center today and arrested 20 people.

Two of the protesters were held for felony charges after police said an officer was knocked off his motorcycle and other officers were kicked, as they moved into the park to tear down illegal tents.

The first mid-afternoon confrontation had police and state troopers shoulder-to-shoulder pushing a group of marchers off the state Capitol steps, which is out-of-bounds to protesters without a permit. Some of the Occupy Denver sympathizers then raced to set up tents in Civic Center, where city officials have allowed ongoing food tables and sleeping bags but not sleeping structures.
Protesters there surged around about eight police officers. Other officers responding to calls for help fired the pepper bullets, which resemble paint balls. One protester filming the scene — one of hundreds of cameras documenting police activity — was knocked out of a tree in the melee.

Five people were arrested in the first conflict, before 3 p.m. Hundreds of officers and SWAT members converged on the park and Broadway was shut down for hours as police and protesters reached a tense stalemate.

About a dozen of the angriest marchers stood nose-to-nose with police and screamed profanity or anti-Wall Street slogans. Others tried to calm the situation, even while filming.