The Constitution authorizes impeachment for "Treason, Bribery, or other high Crimes and Misdemeanors" but never defines the phrase. The Framers rejected James Madison''s proposed "maladministration" standard as too vague—giving the Senate "tenure during pleasure"—and adopted the English Parliament''s term used since 1386 to impeach crown officials. "High" refers to offenses by officials with special duties from oath-taking, not ordinary crimes available to all persons.
Congressional practice shows impeachable conduct includes abusing office power, acting incompatibly with office purpose, or misusing position for personal gain—like violating public trust, obstructing justice, or neglecting duties. This isn''t limited to indictable crimes: Andrew Johnson faced impeachment for firing his secretary of war in defiance of Congress (1868), Richard Nixon for Watergate obstruction before resigning (1974), Bill Clinton for perjury about an affair (1998), and Donald Trump twice—for pressuring Ukraine to investigate Biden (2019) and inciting the January 6 Capitol attack (2021). The Senate acquitted Johnson, Clinton, and Trump because prosecutors failed to convince two-thirds of senators present, demonstrating that impeachment remains fundamentally a political remedy controlled by Congress, not courts.