Article VI, paragraph 3 ("No Religious Test" clause) of the United States Constitution states: "The Senators and Representatives before mentioned, and the Members of the several State Legislatures, and all executive and judicial Officers, both of the United States and of the several States, shall be bound by Oath or Affirmation, to support this Constitution; but no religious test shall ever be required as a qualification to any office or public trust under the United States."
Currently 7 states (Texas, Maryland, Mississippi, Pennsylvania, South Carolina, Tennessee, and Arkansas) unconstitutionally require the acknowledgement of a supreme being in order to hold public office. This is a violation of freedom of (which also includes FROM) religion against atheists.