Felix Frankfurter

“ By thus making the federal judiciary the affirmative agency for enforcing the authority that underlies the congressional power to punish for contempt Congress necessarily brings into play the specific provisions of the Constitution relating to the prosecution of offenses and those implied restrictions under which courts function. ”

“ To turn to the immediate problem before us, the scope of inquiry that a committee is authorized to pursue must be defined with sufficiently unambiguous clarity to safeguard a witness from the hazards of vagueness in the enforcement of the criminal process against which the Due Process Clause protects. ”