As Sen. Bernie Sanders, I-Vt., readies his second presidential campaign in as many cycles, a group of voters is warning him against moving forward with a bid: his own supporters.

Liberal voters from Iowa and elsewhere, all of whom voted for Sanders in 2016, believe the Vermont senator should stand down over concerns about his electability at the national level. With some feeling that his time has past, they want Sanders to pass the torch to a new generation of liberal leaders, including Sen. Elizabeth Warren, D-Mass., and other Democrats who are likely to run in 2020.