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.
The right of assembly was first before the Supreme Court in 18761 in United States v. Cruikshank.2 The Enforcement Act of 18703 forbade conspiring or going onto the highways or onto the premises of another to intimidate any other person from freely exercising and enjoying any right or privilege granted or secured by the Constitution of the United States. Defendants had been indicted under this Act on charges of having deprived certain citizens of their right to assemble together peaceably with other citizens for a peaceful and lawful purpose. Although the Court held the indictment inadequate because it did not allege that the attempted assembly was for a purpose related to the Federal Government, its dicta broadly declared the outlines of the right of assembly:
The right of the people peaceably to assemble for the purpose of petitioning Congress for a redress of grievances, or for anything else connected with the powers or the duties of the National Government, is an attribute of national citizenship, and, as such, under the protection of, and guaranteed by, the United States. The very idea of a government, republican in form, implies a right on the part of its citizens to meet peaceably for consultation in respect to public affairs and to petition for a redress of grievances. If it had been alleged in these counts that the object of the defendants was to prevent a meeting for such a purpose, the case would have been within the statute, and within the scope of the sovereignty of the United States.
https://constitution.congress.gov/browse/essay/amdt1-10-2/ALDE_00000223/