The Impeachers: The Trial of Andrew Johnson and the Dream of a Just Nation by Brenda Wineapple:
A newspaper editor formerly known as an abolitionist, Edmund Gibson Ross was a political nobody who didn’t look a person in the face, dressed in black, and walked with a slouch. He’d been sent to the Senate in 1866 to finish the term after Senator Jim Lane put a loaded gun in his mouth and pulled the trigger. No one quite knew why Lane had committed suicide, though it was rumored he had lost the support of his constituency when he supported Johnson’s veto of the Civil Rights Bill. More likely, financial chicanery was about to be exposed.
Edmund Ross did not in any way distinguish himself in the Senate. A clerk in the House of Representatives regarded him as a lily-livered and malleable man who “may be artfully operated on without his own apprehension of the fact.” Shortly after Johnson was impeached, the National Anti-Slavery sourly commented that “Mr. Ross is suffering from the effects of bad associations.” One of those bad associations was the conservative Thomas Ewing, Jr., under whose command Ross had served during the war. Another was Perry Fuller, who let Ross know it would be to his advantage—Ross’ seat in the Senate—if Johnson was to stay in the White House.