Associated PressThe Los Angeles Police Department's violent response at the end of an immigrant demonstration is the latest incident highlighting what critics describe as the force's "warrior culture."

It's an ethos that's been on display before - the use of clubs and tear gas to disperse 15,000 peaceful antiwar protesters in Century City in 1967; the Watts riots; the Rodney King beating in 1991; the harsh crackdown on demonstrators at the 2000 Democratic National Convention.

Public outcry and inquiries that followed each event have not deterred some officers from cracking a few kneecaps to assert order, even in front of cameras.

Chief William Bratton's criticism of his department and decision to quickly reassign two high-ranking officers after the immigration rally two weeks ago were roundly applauded, though skeptics say it is not nearly enough to address deep-seated issues that produce violent responses by some officers.

Bratton was appointed in 2002 to steer the LAPD after a rogue antigang unit scandalized the department by assaulting and framing people in the tough Rampart district. Dozens of criminal convictions were tossed out as a result of the scandal.

Bratton has since had some success in improving community relations, including his swift action following the May 1 immigration rally violence.

However, skeptics say none of these efforts are enough to address the deep-seated culture that has caused repeated bouts of excessive force.