Trump has demonstrated over and over that he cares nothing about the substance of any deal. He wants praise from whoever is in front of him at the moment and praise from the media, which despite his bashing, he desperately needs to tout his wonderfulness. Unfortunately, that does not work in politics, where the substance matters tremendously to politicians and their supporters. Trump has never been a “Republican” and indeed has never been shy about turning on a dime (e.g. on abortion) if he thought it would benefit him. As a result of his frantic, utterly unprincipled search for a deal, he has essentially convinced both sides that they cannot take him at his word.