Jesse Jackson came to town to speak to demonstrators about black men's deaths in police custody.
Late every Friday, protesters have been gathering in Milwaukee, including at Red Arrow Park, where a police officer shot and killed Dontre Hamilton in April.
They're upset that the DA will not charge former officer Christopher Manney, because the killing was considered self-defense.
Jackson told demonstrators, they cannot be complacent.
"One thing worse than oppression, is to adjust to it. You must ever adjust. You must never explain to yourself, why it's alright, because it's all wrong," Jackson said.
The police chief fired Manney for not following protocol that led to the fatal shooting.
Hamilton, who was mentally ill, had been resting in the park. The officer said Hamilton became combative and struck Manney with his police baton, following a pat down.
