Prosecution always involves strategic tradeoffs, even in simple cases where it's merely the raw dollars needed to pay employees to see someone through the court system for an obvious commitment.
Then there are more complicated cases, for example offering a plea deal in exchange for cooperation that would reign in more important targets.
When it comes to a case like Trump, there is the very real tradeoff where it makes him more powerful, more likely to be reelected, and even more personally wealthy--and same with his family--if charges are brought against him.
Honestly, I'd say the worst punishment for him would be to leave him for obscurity, a failed candidate rejected by voters.
That might be the best justice for him, even worse than what punishment the law could dole out.
