The Starr investigation of President Clinton raised a basic constitutional issue affecting the separation of powers, whether and when a president must obey a subpoena to testify in judicial proceedings. Presidents might reasonably claim a constitutional immunity from being compelled to present themselves before a judge. The congressional impeachment power is ultimately the best mechanism for evaluating the appropriateness of such a presidential claim and for enforcing compliance with a subpoena when presidential grounds for ignoring judicial orders are deemed inadequate. The president should be most concerned with adhering to an appropriate vision of constitutional ethics, not with providing minimal compliance with legal technicalities.