All right, "high crimes" is a big deal, but aren't all kinds of Mickey Mouse things misdemeanors? Or: is it high "crimes and misdemeanors," not just regular misdemeanors. What is a "high misdemeanor"? Briefly, and late in the convention, the framers addressed the question how to describe the grounds for impeachment consistent with its intended function. They did so only after the mode of the President's election was settled in a way that did not make him (in the words of James Wilson) "the Minion of the Senate." 45 The draft of the Constitution then before the Convention provided for his removal upon impeachment and conviction for "treason or bribery." George Mason objected that these grounds were too limited: Why is the provision restrained to Treason & bribery only? Treason as defined in the Constitution will not reach many great and dangerous offenses. Hastings is not guilty of Treason. Attempts to subvert the Constitution may not be Treason as above defined-As bills of attainder which have saved the British Constitution are forbidden, it is the more necessary to extend: the power of impeachments.46 ​ Mason then moved to add the word "maladministration" to the other two grounds. Maladministration was a term in use in six of the thirteen state constitutions as a ground for impeachment, including Mason's home state of Virginia.47 When James Madison objected that "so vague a term will be equivalent to a tenure during pleasure of the Senate," Mason withdrew "maladministration" and substituted "high crimes and misdemeanors agst. the State,"which was adopted eight states to three, apparently with no further debate.48 That the framers were familiar with English parliamentary impeachment proceedings is clear. The impeachment of Warren Hastings, Governor-General of India, for high crimes and misdemeanors was voted just a few weeks before the beginning of the Constitutional Convention and George Mason referred to it in the debates. 49  Hamilton, in the Federalist No.65, referred to Great Britain as "the model from which [impeachment] has been borrowed." Furthermore, the framers were well-educated men. Many were also lawyers. Of these, at least nine had studied law in England.50 The Convention had earlier demonstrated its familiarity with the term "high misdemeanor."51 A draft constitution had used "high misdemeanor" in its provision for the extradition of offenders from one state to another.52 The Convention, apparently unanimously struck "high misdemeanor" and inserted "other crime," "in order to comprehend all proper cases: it being doubtful whether 'high misdemeanor' had not a technical meaning too limited."53 The "technical meaning" referred to is the parliamentary use of the term "high misdemeanor." Blackstone's Commentaries on the Laws of England- a work cited by delegates in other portions of the Convention's deliberations and which Madison later described (in the Virginia ratifying convention) as "a book which is in every man's hand"54 - included "high misdemeanors" as one term for positive offenses "against the king and government. " The "first and principal" high misdemeanor, according to Blackstone, was "mal-administration of such high officers, as are in public trust and employment," usually punished by the method of parliamentary impeachment."55 "High Crimes and Misdemeanors" has traditionally been considered a "term of art," like such other constitutional phrases as "levying war" and "due process." The Supreme Court has held that such phrases must be construed, not according to modern usage, but according to what the farmers meant when they adopted them.56 Chief Justice Marshall wrote of another such phrase: It is a technical term. It is used in a very old statute of that country whose language is our language, and whose laws form the substratum of our laws. It is scarcely conceivable that the term was not employed by the framers of our constitution in the sense which had been affixed to it by those from whom we borrowed it.57​ (From a post by waiguoren: https://forums.sherdog.com/threads/defining-high-crimes-and-misdemeanors.4042817/