How many Senators were willing to vote for acquittal ?
Senators William Pitt Fessenden ( Maine ) , Joseph S. Fowler ( Tennessee ) , James W. Grimes ( Iowa ) , John B. Henderson ( Missouri ) , Lyman Trumbull ( Illinois ) , Peter G. Van Winkle ( West Virginia ) , and Edmund G. Ross ( Kansas ) , who provided the decisive vote , defied their party by voting against conviction .