"The charge of high crimes and misdemeanors covers allegations of misconduct by officials, such as dishonesty, negligence, perjury of oath, abuse of authority, bribery, intimidation, misuse of public funds or assets, failure to supervise, dereliction of duty, unbecoming conduct, refusal to obey a lawful order, chronic intoxication, including such offenses as tax evasion. Offenses by officials also include ordinary crimes, but perhaps with different standards of proof and punishment than for non-officials, on the grounds that more is expected of officials by their oaths of office. The word "High" refers to the office and not the offense. Indeed the offense may not even be a breach of criminal statute.”
See Harvard Law Review "The majority view is that a president can legally be impeached for “intentional, evil deeds” that “drastically subvert the Constitution and involve an unforgivable abuse of the presidency” — even if those deeds didn’t violate any criminal laws."
