Rep. Keith Ellison (D-MN) is urging Bernie Sanders supporters at the Democratic convention to come together and rally behind Hillary Clinton or risk electing Donald Trump.

As Sanders delegates hint they could walk out on Clinton’s acceptance speech at the Democratic convention, Ellison – who endorsed Sanders– is urging them to think about the bigger picture.

“I am just saying the logic of playing spoiler to the advantage of Trump does not make any sense to me if you call yourself a Bernie supporter,” Ellison told TPM in a phone interview Monday.

Ellison told TPM that he spent Monday meeting with state delegations and reaching out to Sanders supporters in person and on social media. He said he will continue his efforts on the convention floor throughout the week. And while he supports people acting on their beliefs, he worries some are losing sight of the “real bullies.”

Ellison said he is proud of the movement Sanders built, but that if “Bernie or Bust” delegates and supporters aren’t careful “they are going to sabotage the whole Democratic process in favor of Donald Trump.”

“I want someone to explain to me how they are Bernie or bust but Bernie is not,” Ellison said.