1. When a constitutional crisis leads a President to usurp power, the Congress is discharged and the constitution suspended. Clearly, a constitutional stipulation authorizing the executive and legislative branches to exercise independent authority by no means assures the survival of such a system. In any test of strength, a President can normally quash the Congress. The basic rule sustaining a presidential regime is the requirement that the head of government be elected for a fixed term, not subject to dismissal by a legislative vote of no confidence. Impeachment is not such a vote since it is a judicial procedure designed to oust Presidents guilty of "high crimes and misdemeanors" and does not automatically lead to a change of government but only to the replacement of the President by someone (e.g., a vice president) of the same political persuasion. Although Congress sometimes overshadows the President in presidentialist regimes, I do not know of