Democrats
Julian Castro
Cory Booker
Al Franken
Joseph Kennedy III
John Hickenlooper
Gavin Newsom
Antonio Villaraigosa
Ron Wyden
Chris Murphy
Republicans
Kelly Ayotte
Tom Cotton
Bobby Jindal
Rand Paul
Cory Gardner
Marco Rubio
Joni Ernst
Ted Cruz
Brian Sandoval
Charlie Baker
Libertarian
Justin Amash
I don't see any way Kennedy would be ready by 2020. He would be the youngest president ever elected and has very little national spotlight outside of his lay name. Only one president has been elected directly from the house. I could maybe see him for 2024 if Markey retires and he becomes senator in 2018. 2028 could work. By 2024 I assume Warren or Markey will be retired.
Yeah, I guess it was a bit of a stretch to put him on there for 2020. I'd like to see another Kennedy in the White House at some point!