Incorporation applies both procedurally and substantively to the guarantees of the states. Thus, procedurally, only a jury can convict a defendant of a serious crime, since the Sixth Amendment jury-trial right has been incorporated against the states; substantively, for example, states must recognize the First Amendment prohibition against a state-established religion, regardless of whether state laws and constitutions offer such a prohibition. The Supreme Court has declined, however, to apply new procedural constitutional rights retroactively against the states in criminal cases ("Teague v. Lane", ) with limited exceptions, and it has waived constitutional requirements if the states can prove that a constitutional violation was "harmless beyond a reasonable doubt."