On Wednesday, the Senate acquitted President Trump, bringing to an end a months-long effort by Democrats to remove him from office. Jeffrey A. Engel is director of the Center for Presidential History at Southern Methodist University and co-author of “Impeachment: An American History.” He joins host Krys Boyd to talk about how the Trump impeachment differed from the impeachments of Andrew Johnson and Bill Clinton – and about how it will affect future impeachment proceedings.