The First Amendment to the United States Constitution provides that Congress shall make no law abridging (curtailing) the right of the people to peaceably assemble. And the U.S. Supreme Court has determined that a right to freedom of association and belief is implicit in the First, Fifth, and Fourteenth Amendments. But this right to freedom of assembly is limited to First Amendment purposes and does not include a right to assemble for social purposes or to engage in or promote illegal activities. And when there is a right of association, the government may not require the group to disclose the identity of its members, or deny government benefits on the basis of current or past membership in a group.

In Missouri, as in all states, the right to peaceably assemble is protected under the First Amendment of the United States Constitution. This means that individuals and groups in Missouri have the right to gather for peaceful protest, public demonstrations, and other expressive activities without undue interference from the government. The U.S. Supreme Court has also recognized a broader right to freedom of association and belief, which is protected by the First, Fifth, and Fourteenth Amendments. However, this right is not absolute and does not extend to gatherings organized for social purposes unrelated to expression or for the purpose of engaging in or promoting illegal activities. Additionally, while the government generally cannot force a group to disclose its members' identities or deny benefits based on membership in a particular group, there may be exceptions, particularly when there are compelling state interests at stake, such as public safety or national security. Missouri state statutes and local ordinances must comply with these constitutional protections, but they may regulate the time, place, and manner of assemblies to ensure public order and safety, provided that such regulations are content-neutral and narrowly tailored to serve a significant governmental interest.