‘Bernie or Bust’ Voters Create Predicament for Democrats in 2020

The fierce loyalty Bernie Sanders inspires in his supporters is creating a dilemma for the Democratic Party.

For a sliver of Sanders’ base, it’s Bernie or bust. They may detest President Donald Trump, but they didn’t vote for Hillary Clinton and they’re not sure they’ll back the Democratic nominee in 2020 if Sanders isn’t on the ballot. They’re willing do whatever it takes to push the party to adopt his ideas.

“Sometimes things have to get ugly before they get better,” said Melissa Mallaber, a 46-year-old social worker who attended...