A look back at presidential impeachment in U.S. history

Impeachment is a rare event in American politics. Amid the past few weeks of public hearings, we have wondered how this episode compares to previous instances of impeachment. Amna Nawaz spoke with three historians, each focused on a former president who had to grapple with that threat: Peter Baker on Bill Clinton, Timothy Naftali on Richard Nixon and Brenda Wineapple on Andrew Johnson.