The apogee of 1990s constitutional hardball was the December 1998 House vote to impeach President Clinton. Only the second presidential impeachment in U.S. history, the move ran afoul of long-established norms. The investigation, beginning with the dead-end Whitewater inquiry and ultimately centering on President Clinton's testimony about an extramarital affair, never revealed anything approaching conventional standards for what constitute high crimes and misdemeanors.