According to the Constitution, the POTUS may be impeached for high crimes and misdemeanors. Hamilton, Federalist 65, defines high crimes and misdemeanors as "...proceed from the misconduct of public men, or in other words from abuse or violation of some public trust. They are of a nature which may with peculiar propriety be denominated POLITICAL, as they chiefly relate to injuries done immediately to the society itself." Fascinatingly, their is no legal or objective definition for the term, meaning that is it subject to much interpretation. Cheers!