A decline of public morals in the United States will probably be marked by the abuse of the power of impeachment as a means of crushing political adversaries or ejecting them from office.

It was John Innes Clark Hare in his book "American Constitutional Law - Volume 1" who claimed that this was from Toqueville in an unsourced paraphrase that started with "It was long since remarked by De Tocqueville..." Actual quote, from Toqueville's Democracy In America, Chapter VII: "When the American republics begin to degenerate it will be easy to verify the truth of this observation, by remarking whether the number of political impeachments augments."