You are right about Hillary and Sanders but I don't think Booker has any chance although he will certainly be a player. If Trump does not deliver, a Democrat will be the next POTUS but it might be a new face. Warren will also stay in the forefront but she will never win.
Like mule, that's who I'm picking, too. Dems need to find someone who'll motivate just enough of those too-lazy-to-vote-in-2016 Lefty kids to get off the couch next time (though mathematically, it won't really take
that many more). Maybe some of the today's rioters will grow up and actually decide to register to vote, too.
Not sure who else on the Left can do it, but Booker obviously fits the profile. And I don't necessarily mean color; though I'm certain the Dems.....who'll certainly be delighted to play that card after Trump spends 4 years kicking the living **** out of them.....will remember how the right kind of guy can deliver. Plus, Obama will be going crazy for Booker.....not that it did Hillary much good. Hell, he's liable to end up running Booker's campaign.
Meanwhile, if Trump can win, the notion of a "no chance/can't win/will never win" candidate just went into the ******* for the rest of time. And as for Warren, she's certainly got a big enough mouth to keep Trump honest on stage in a debate.