In 1868 Congress impeached President Andrew Johnson of Tennessee, the man who had succeeded the murdered Lincoln, bringing the nation to the brink of a second civil war. Enraged to see the freed slaves abandoned to brutal violence at the hands of their former owners, distraught that former rebels threatened to regain control of Southern state governments, and disgusted by Johnson's brawling political style, congressional Republicans seized on a legal technicality as the basis for impeachment -- whether Johnson had the legal right to fire his own secretary of war, Edwin Stanton.
