> particularly political partisans
I think I identified the problem. Hey, let's boil down all complex answers to complex problems along a 1-dimensional axis and then completely and voluntarily ignore half that axis! What could possibly go wrong?
> how much does presentation matter?
A lot, in my experience trying to change minds.
> can we present the same facts in a way that is more pallatable?
Humor is perfect for this. "If you want to tell people the truth, make them laugh, otherwise they'll kill you." -Oscar Wilde
> what if we tried to coax the audience into believing they came to the conclusion from the facts themselves?
This is much easier to do on an individual basis than en masse. You basically hand-hold someone down their line of thinking until you get to the dissonance, then comes the important bit, you take a step back. If the person feels coerced in any way, they will push back, which is why you simply try to walk them down their own train of thought. Eventually they will stumble, especially if you gently lay some facts in the way... At all times you must respect their opinion.
All of this would be much easier if people didn't tie their egos to their beliefs so tightly.