When the great American Civil War ended on the battlefield, much of the South did not admit defeat. The battle was merely transferred to defeating all forms of civil rights coming out of Washington DC.
After Lincoln was assassinated and replaced by the despicable Andrew Johnson (the racists president Trump most resembles), who was impeached , but missed conviction by a single vote, U. S. Grant became president and did all he could to defend Negro rights in the South, even though his administration was infested with much corruption.
But after Grant there were a series of presidents indifferent to civil rights. The South was allowed to returned to a form of virtual slavery know as the Jim Crow era until the 1960s.
But right up until today Washington remained under attack by the forces of division and hate. Drain the swamp is merely the latest attempt by Souther forces (as best represented by the KKK) to defeat the nation’s better angels.