I don't think Trump can actually "dispense with" trial by jury. He only gets away with what he does under the aegis of having plenary authority over the executive branch, (which I don't think he actually does but no one seems to care) but he doesn't control the judicial branch. And the courts seem to be the only branch of government putting up any resistance at all.

Although he could just ignore the courts entirely or just start black-bagging judges he disagrees with, but for whatever reason he hasn't taken it that far. And while I despise the American military as much as any person with any moral fiber should, at least they do seem to believe in the Constitution enough to tell Trump to fuck off as they did during his first term, so the option of a military coup doesn't seem on the table for him either.