Kennedy, LBJ, Clinton, Obama....
The trick is to elect a President who is compromised, and thus controllable.
Remember how they put the hurt on Senator Bob Menendez when he refused to go along with the Iran Deal? The day after he announced his dissent, the stories about underaged Dominican hookers showed up in the New York Times. As soon as Menendez agreed to play ball, they disappeared.
Having compromising information on a politician makes him infinitely more valuable. So the question is, what does the DNC have on Creepy Uncle Joe?