I always get a kick out of people who ask the exact right question, rhetorically, when the literal answer is squarely the one needed to counter their stance.
Case in point, a clip of #Trump stumping with, "How can [they] put me on trial during an election campaign[..]?"
Well, sure, sir, let's walk you through how the judicial process works in the US, since it sounds like you could use a review, and then cover how your own choices opened you up to that process.
That should be a pretty complete answer to "How?" ... thanks for asking.
But mainly, I think I've heard lawyers say to never ask a witness a question when you're not positive the answer would support your case.
It's good advice in general.