From a political science standpoint, it is worth pointing out that most politicians at least try to fulfill their campaign promises, and most promises are sincere reflections of their personal beliefs. A great book that applies in most cases: Jacobs & Shapiro's Politicians Don't Pander. Basically, candidates look for ways to pitch what they want to do anyway in palatable terms, and try to actually do it regardless of what people want. But at least they don't pander!
Trump, though, has no real policy beliefs. He's not a politician! He just says whatever he thinks will get traction at the time, with no long-term plan. So, he is backing away from everything, or at least giving himself wiggle room. That leads to some deep ironies. In the case of prosecuting Clinton, it was a dilemma of throwing out democratic norms by prosecuting a vanquished opponent, or throwing out democratic norms by immediately disregarding a campaign promise central to his campaign, rallies and convention.
That kind of thing wouldn't be necessary for someone with a long-term plan, coherent beliefs, etc.