the last book I ever read (The Impeachers: The Trial of Andrew Johnson and the Dream of a Just Nation by Brenda Wineapple, excerpt fourteen)

from The Impeachers: The Trial of Andrew Johnson and the Dream of a Just Nation by Brenda Wineapple:

Like Lincoln, those who understood that slavery had caused the war also understood how it was slavery that lay behind Johnson’s impeachment. And thus not to eliminate the monstrous power of slavery or its aftereffects, and not to prevent its recurrence in any form, Charles Sumner declared, “leaves the country prey to one of the most hateful tyrannies of history.”

To forget, then, that it was slavery, pernicious slavery, that lay behind the impeachment of Andrew Johnson is to ignore Lincoln’s response to succession, to the war, and hence to slavery itself. “If slavery is not wrong,” Lincoln had said, “nothing is wrong.”