> Subsequently ruined by politicians. <
Subsequently ruined by John Wilkes Booth.
Assassinations rarely work out the way the assassins think they will. Lincoln had given Grant the authority to "let 'em up easy", and he was using it.
Andrew Johnson had no such restraining influence over the Radicals as Lincoln would have had.
Much racial bitterness and sectional acrimony would have been avoided if Booth and company had just dropped their big schemes.