In our politically charged climate, it’s not uncommon to hear about impeachment. Earlier this month, a billionaire environmentalist launched a campaign to impeach President Trump. How does the process of impeachment really work? What’s an impeachable offense? And how many presidents have been impeached? Harvard Law professor Cass Sunstein offers a nonpartisan, historical guide — with some reverence — and even awe, for our constitutional order, and for the power it gives We the People. Sunstein’s latest book Impeachment: A Citizen’s Guide is out this month.