Matt Borges supported his state's governor, John Kasich, in the primary.
“I was personally really pissed off,” one former staffer told The Daily Beast.
“Nevada’s always close,” he told the crowd, “but that’s what makes it exciting.”
Trump said he didn’t believe in deporting illegal immigrants who “had done a great job."
The merger would make AT&T the owner of media companies including CNN.
Clinton promoted fellow Democrats in down-ballot races.
"Man, I wouldn't want people speaking ... about me behind my back," Trump said.
The woman wore a shirt that said "Latinas contra Trump."
The event is scheduled to begin at 6 p.m.
AT&T has reached a deal to buy Time Warner for $85.4 billion.