The US has never ratified Protocol II of the Geneva Conventions, which has to do with humanitarian violations of the State during times of non-international conflict. Thus, Protocol II is non-binding on US soil, meaning agents of the State can do whatever they want to domestic protestors without international repercussions. If the US ratified Protocol II, police could be held responsible for offenses such as intentionally running over protesters with cars/horses, arresting members of the press, shooting people in the face at point-blank range, and other inhumane treatment. As of today, the United States, Iran, and Pakistan are the only nations to have signed but not ratified Protocol II. Read more here.