Leaning into the bar at the debate’s conclusion, Margheim sipped the last of her beer and looked around. She wondered how many of her compatriots were caught in the same dilemma. “I mean, I live with four other girls, and we’re all stuck between Warren and Sanders,” she said. “It’s the policy details and passion of Warren, versus the charisma and grassroots energy of Bernie. And my gut still hasn’t led me one way or the other.”

The indecision didn’t scare her until the events of this week. Just in the past few days, Margheim said, she’s begun to see attacks, online and elsewhere, mounted by friends and classmates loyal to one of the two candidates: Warren fans questioning Sanders’s age and health and electability, Sanders fans challenging Warren’s authenticity and her commitment to progressive ideals. Suddenly, Margheim fears, caucusing might feel less like making a choice and more like picking a fight.

“It’s really unnerving,” she said. “I hope it doesn’t just hurt them both.”