It's tough to say. Elizabeth Warren makes sense. Cory Booker does too. But there are 2018 elections that will shape a lot of political careers and thus the ensuing run at 2020 or not.
Time for a Kardashian to run. They've had their black president, no doubt they'll want to try again for a woman. And if Kim gets the job Bruce, pardon, Caitlyn, would be a shoe in for the following election. Perhaps he could even claim Indian ancestry like that Warren fraudster. Democrats would shower their keyboards, TVs, and each other in ejaculate at that one.