Such serious charges by so many distinguished historians demand a careful consideration of what the Founders meant by "high Crimes and Misdemeanors": Were they only indictable crimes or did they include what one of the Framers called "political crimes and misdemeanors?" Were they offenses that a President would commit only in "the exercise of executive power" or did they also include a President's malfeasance committed in his private capacity? Were they subject to a reasonably fixed meaning or were they to be determined simply by the exercise of the "awful discretion" of those in Congress called upon to impeach and to try impeachments? If it is true that this new theory of impeachment will indeed "leave the Presidency permanently disfigured and diminished [and] at the mercy as never before of the caprices of any Congress," then a return to the proper understanding of the Founders' intentions will avert nothing less than a constitutional catastrophe.
Gary L. McDowell, "High Crimes and Misdemeanors": Recovering the Intentions of the Founders, 67 Geo. Wash. Int'l. L. Rev. (1999).