|PT Barnum with his VP pick, Commodore Nutt|
Donald Trump's offfer to debate Bernie Sanders for charity is a typical bit of PR genius.
First of all, Sanders would be crazy to turn it down. It gives him some free publicity Hillary Clinton will not get, on the eve of the crucial California primary. It also lets Sanders fix the image in Democrat voters' minds of himself as the nominee. And it puts in voters' minds the image of Sanders as the natural opponent of Donald Trump, aka the Devil Incarnate to many Democrats. Given all these considerations, the event is pretty likely to happen.
Even if it doesn't, Trump wins. The offer itself is a news story keeping him in focus instead of just the Dems. Because it is for charity, and specifically an unspecified women's charity, Trump can then say that Democrats do not really care about women, while he does. And, of course, he can claim that Sanders is scared of him.
But the true art of the deal is to come up with a win/win proposition. That is what this is. Sanders should thank Trump for the opportunity.
For Trump, it gives him a big jolt of free publicity. Especially if the offer is accepted, it injects him into the news cycle just as, otherwise, everyone would be focusing only on the Democratic race. In particular, it takes the spotlight off Hillary, his most likely opponent, diminishing her. Boosting Sanders also makes eventual unity harder for the Democrats. The closer Sanders comes to being the Democratic pennant-bearer, the stronger will the temptations be to launch a third-party bid, vitrually handing the presidency to Trump.
It all works best if, as is far more likely, Hillary still ends up being the Democratic nominee. But if Sanders comes close enough that she wins only on the strength of the automatic delegates representing the party establishment, it makes Trump look that much more like the candidate of the common man. But even if it overshoots and hands Sanders the nomination, or something does, it is still not a bad thing for Trump. At worst, the Democratic nominee is getting no more exposure than he is. Some might also argue that Sanders would be easier to run against; I'm not at all sure about that. His policies might be less popular than Hillary's, but people are more inclined to vote on personalities.
It shows once again Trump's PR talents. He is, if nothing else, a great salesman. And the American people love that sort of showmanship. It is in the fine tradition of P.T. Barnum and W.C. Fields, the Yankeee pedlar and the emcee of the Old West medicine show. Sure, Barnum was a liar and a cheat, and the patent medicine probably did not work, but the lie and the cheat were so entertaining, they were more than worth the price of admission. It is popular entertainment in the fine, culturally democratic, American tradition.