As dozens of journalists filled the back of the ballroom, Bethany Khan, a spokeswoman for the powerful Culinary Workers Union, which represents many of the workers who attended Saturday’s Bellagio caucus, drifted around the ballroom in a red union T-shirt and gold-sparkle tennis shoes. Were they for a special occasion? “This is a normal outfit, because it’s Vegas,” Khan said.

“I don’t think it’s cooled off,” Khan said of the controversy. “Maybe [more] people are calling to say they respectfully disagree, rather than yelling at me.”

Technically, although the leadership had made plain its affinity for former Vice President Joe Biden and its distrust of Sanders, the union had not endorsed anyone, meaning the members filing into the ballroom were “deciding for themselves who they want to caucus for today,” Khan said.