In The Great Shark Hunt: Strange Tales from a Strange Time, Hunter S. Thompson relates the following tale:

This is one of the oldest and most effective tricks in politics. Every hack in the business has used it in times of trouble, and it has even been elevated to the level of political mythology in a story about one of Lyndon Johnson’s early campaigns in Texas. The race was close and Johnson was getting worried. Finally he told his campaign manager to start a massive rumor campaign about his opponent’s life-long habit of enjoying carnal knowledge of his own barnyard sows.

“Christ, we can’t get a way calling him a pig-f%$#er,” the campaign manager protested. “Nobody’s going to believe a thing like that.”

“I know,” Johnson replied. “But let’s make the sonofabitch deny it.”

Well, right now, the UK is transfixed by the tale of PM David Cameron and Piggate:

Late last night, the Daily Mail published an astounding excerpt of an unauthorized biography of UK Prime Minister David Cameron, alleging that he placed a “private part” of his body into the mouth of a dead pig’s head while at Oxford University.
He put his nob in a pig’s mouth. Popped his todger into the poor swine’s gob.
It’s crucial when dealing with such an important and weighty story to have all the facts, so please let this Brit guide you through the revolting tale of prime ministerial pig porkery.

It is claimed that there are pictures, but this could be a, “Make the sonofabitch deny it,” moment.

In either case, this is a profoundly weird moment in politics.