Nixon is basically a choir boy compared to FDR, LBJ, the Clintons, and Obama/Biden when it comes to electoral fraud, identification and intimidation of political opponents, spying on citizens, etc.
Nixon did nothing by comparison; the goals of the Dems were two-fold - they wanted him out of office in revenge for Alger Hiss and his fellow travelers and they wanted to defeat any chance that the ARVN could withstand the NVA communist army. Bad people, all of them, and one wretched Hillary Clinton, despite having flunked the DC bar exam, was one of the lawyers on the impeachment committee.