In our politically charged climate, it’s not uncommon to hear about impeachment. 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 book "Impeachment: A Citizen’s Guide" was released in 2017. He spoke at Aspen Ideas on June 28, 2017.