A lot can happen between now and Election Day -- and with no GOP adult in the room, that's a frightening thought.There was a time when the well-worn “clown car” description of the Republican presidential primary field wasn’t so on-the-nose. But as of right now, not even a few months into the process, it’s impossible to avoid daily news items in which one GOP candidate or another is self-immolating with ludicrous remarks or unforced errors. Frankly, it’d be really fun to observe if it weren’t for a nagging sense of danger. We’ll circle back to that. Meanwhile, Sen. Marco Rubio,...