2020 Watch: Democrats (and some Republicans) lay the groundwork for a presidential run09:04
Fmr. V.P. Joe Biden, Ohio Gov. John Kasich (R), Sens. Bernie Sanders (I-Vt.), Cory Booker (D-N.J.), Elizabeth Warren (D-Mass.) and Ben Sasse (R-Neb.) have all written books, and traveled to early primary states, potentially planning a presidential run in 2020.