...With this background of constitutional history and practice in mind, certain conclusions may be drawn. First, the substantive grounds for impeachment are not limited to criminal offenses. The phrase "high Crimes and Misdemeanors" was historical terminology which encompassed breaches of public trust not amounting to crimes. On the other hand ... it is fair to conclude that the Framers had in mind that only conduct which in some broad fashion injures the interests of the country as a political entity be the basis for impeachment and removal. The phrase "other high Crimes and Misdemeanors" should accordingly be construed as referring only to acts which, like treason and bribery, undermine the integrity of government...

It is our conclusion, in summary, that the grounds for impeachment are not limited to or synonymous with crimes (indeed, acts constituting a crime may not be sufficient for impeachment of an officeholder in all circumstances). Rather, we believe that acts which undermine the integrity of government are appropriate grounds whether or not they happen to constitute offenses under the general criminal law. In our view, the essential nexus to damaging the integrity of government may be found in acts which constitute corruption in, or flagrant abuse of the powers of, official position. It may also be found in acts which, without directly affecting government processes, undermine that degree of public confidence in the probity of executive and judicial officers that is essential to the effectiveness of government in a free society. What specific acts meet this test will vary with circumstances, including the particular position in government held by the person charged.

-Committee on Federal Legislation, Association of the Bar of the City of New York, The Law of Presidential Impeachment, 29 The Record (1974) [emphasis added]