Freedom of Association/Legal Codification/US
Is it contained in the US Constitution?
No.
The right to free association is not explicitly stated in the United States Constitution. Though, The Supreme Court has historically upheld the constitutional right to free association, invoking the Fourteenth and First Amendments (Legal Information Institute, Cornell Law School). In 1958, The NAACP v. Patterson ruling established this precedent. In response to Alabama’s aims to limit the NAACP’s business within the state, the Supreme Court ruled that it was “the right of petitioner's members to pursue their lawful private interests privately and to associate freely with others in doing so as to come within the protection of the Fourteenth Amendment” (Oyez). Furthermore, the court asserted that freedom of association was undoubtedly covered by the Due Process Clause of the Fourteenth Amendment (Oyez), which asserts no individual may be “"deprived of life, liberty or property without due process of law.” The court additionally demonstrated the First Amendment to protect free association, Justice Harlan claiming “Effective advocacy of both public and private points of view, particularly controversial ones, is undeniably enhanced by group association, as this Court has more than once recognized by remarking upon the close nexus between the freedoms of speech and assembly.” Thus, while the right to free association is not explicitly described by the Constitution, as witnessed in NAACP v. Patterson, it is upheld by American constitutional law.
References:
Cornell Law School, Legal Information Institute, “First Amendment”: https://www.law.cornell.edu/wex/first_amendment