LAS VEGAS (AP) — As a diverse crowd filled a college student union this week, they swapped stories of seeking refuge in the U.S. or living in households that were a mix of U.S. citizens and people in the country illegally. They hoped to share their experiences with presidential candidates seeking support ahead of Saturday’s Nevada caucuses.

But only one White House hopeful showed up: Tom Steyer, a billionaire long shot. Most other campaigns sent surrogates to the event, sponsored by Amnesty International, while the candidates themselves appeared on cable television or stumped in other states.

The caucuses mark the first time this primary season that the Democratic contest moves to a state with a significant minority population. About one out of five residents in Nevada is an immigrant and President Donald Trump’s hard-line stance on immigration has turned the issue into a cultural and political touchstone. But by avoiding forums like the one held at the College of Southern Nevada, candidates left some residents with the impression that Democrats don’t want to talk about immigration even as they seek their votes.

“This is an issue that we know Donald Trump has absolutely been weaponizing to expand his base and that he’s been weaponizing to target every person of color,” said Lorella Praeli, a prominent Democratic operative and activist who was Hillary Clinton’s Latino outreach director in 2016. “I’m enraged at the fact that candidates and the media are operating in a different world where none of these things are happening.”

Activists complain that few immigration questions were asked at several of the nine Democratic debates, and were upset after the issue got only one question on Wednesday night in the Las Vegas face-off. Candidates have also been careful about getting into too much detail on the stump about a subject that has become a political minefield.

Many of the leading Democratic candidates have baggage on the issue, a reflection of how the politics of immigration have changed over the past two decades. Republicans and Democrats once strove to balance enforcement and humane treatment of immigrants. But since 2012, Republicans have doubled-down on immigration enforcement and deportations while Democrats have focused on fighting deportations and ensuring humane treatment.

Former Vice President Joe Biden has regularly been targeted by activists — including one Thursday night who said she wouldn’t feel safe if he were president — protesting the high rate of deportations under the Obama administration. Vermont Sen. Bernie Sanders helped kill a bipartisan immigration bill in 2007 by joining a group of liberals who compared its guest worker provisions to “slave labor.” Minnesota Sen. Amy Klobuchar once pushed for English to be made the official language of the United States, and former New York City Mayor Mike Bloomberg supported a “stop-and-frisk” police program that targeted Hispanics along with African-Americans for constant searches.