- Andrew Johnson was the first US President to be impeached. He is generally considered to be one of the worst Presidents, though one could easily argue it’s not entirely his fault. He was the only senator from a seceding state to remain pro-Union, so he was chosen as Lincoln’s running mate to broaden the ticket’s appeal and garner votes from Southern sympathizers. He was never intended to be anything other than a grab for votes. Then Lincoln got shot. Oops.