The ACLU has created several documents to assist both the participants and observers of protests. The information presented here is especially important for those participating or witnessing protests that involve interactions with the police.
Attached you will find some of those documents. They include:
1.) A pamphlet outlining which protest actions generally qualify as "lawful" and which fall into the category of non-violent civil-disobedience. This pamphlet also has important information about what to do if questioned or taken into custody by police during a protest.
2.) A legal observer guide published by the National Lawyer's Gild
3.) An ACLU pocket card that gives general advice about your rights if you are stopped by police. This is advice is not protest specific but could apply in many protest situations.