“ I agree that Florida may require state employees to affirm that they 'will support the Constitution of the United States and of the State of Florida.' Such a forward-looking, promissory oath of constitutional support does not in my view offend the First Amendment's command that the grant or denial of governmental benefits cannot be made to turn on the political viewpoints or affiliations of a would-be beneficiary. ”

“ However, in striking down the latter oath, the Court has left the clear implication that its objection runs, not against Florida's determination to exclude those who 'believe in the overthrow,' but only against the State's decision to regard unwillingness to take the oath as conclusive, irrebuttable proof of the proscribed belief. Due process may rightly be invoked to condemn Florida's mechanistic approach to the question of proof. ”

“ But in my view it simply does not matter what kind of evidence a State can muster to show that a job applicant 'believe (s) in the overthrow.' For state action injurious to an individual cannot be justified on account of the nature of the individual's beliefs, whether he 'believe (s) in the overthrow' or has any other sort of belief. 'If there is any fixed star in our constitutional constellation, it is that no official, high or petty, can prescribe what shall be orthodox in politics, nationalism, religion, or other matters of opinion * * *.' West Virginia State Board of Education v. ”