Peaceful Assemble Or Riot?
Bill of Rights, First Amendment. "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the government for a redress of grievances."
"... if the First Amendment guarantees the right to peaceable assembly, why do peaceful protestors keep getting arrested — and sometimes pepper-sprayed and beaten up?" "The First Amendment is not absolute. Government can make reasonable stipulations about the time, place and manner a peaceable protest can take place, as long as those restrictions are applied in a content-neutral way." This article is basically saying that the First amendment does not specify what exactly a peaceful assemble is. Therefore, the police are authorized to step in to any assemble that thy consider to be "un-peaceful". (Source: http://www.propublica.org/article/explainer-just-how-much-can-the-state-restrict-a-peaceful-protest )