Find his long lost lesbian daughter. Find those pedophile pictures he has in his basement. Scrounge up the credit card charges for escort services he used when on the road campaigning for his "moral"
The beauty of it is, it doesn't even have to be accurate (this election; indeed, this thread has shown that). Just manufacture some good "evidence" (Hollywood should be good for that), make sure it gets high publicity, repeat every 2-3 months with something new (must reinforce the meme periodically, or the Eloi will forget).
There is a certain Karmic balance of the "his own medicine" approach....