A ballot measure in Colorado that would, if passed, make the state the first in the country to have universal, government-run healthcare is facing resistance from a surprising group: state Democrats.

ColoradoCare, as it’s being called, has given ammunition to Republicans looking to attack Obamacare-supporting politicians during the campaign season. That has prompted establishment Democrats to come out against the plan, revealing a split between populist voters who support Bernie Sanders and pro-Clinton politicians, such as Governor John Hickenlooper and US senator Michael Bennet.