A State's power to inquire about a person's beliefs or associations is limited by the First Amendment, which prohibits a State from excluding a person from a profession solely because of membership in a political organization or because of his beliefs.
Baird v. State Bar of Arizona, 401 U.S. 1 (1971), was a United States Supreme Court case in which the Court ruled:
A State's power to inquire about a person's beliefs or associations is limited by the First Amendment, which prohibits a State from excluding a person from a profession solely because of membership in a political organization or because of his beliefs.
In this case, a law school graduate who had passed the Arizona written bar examination had applied to be admitted to the Arizona bar, but had refused to answer a question as to whether she had ever been a member of the Communist party. On that basis, the State Bar of Arizona refused to admit her.
McChrystal, Michael K. (1989). "Legitimizing Realities: State-Based Bar Admission, National Standards, and Multistate Practice". Georgetown Journal of Legal Ethics. 3: 533. ISSN1041-5548.