GOP presidential candidates will debate Wednesday, this time in Colorado, a swing state that cannot be won without at least 44 percent of its Latino vote, according to recent studies.

That’s a tall order for candidates who have been far from friendly to immigration reform that would provide a path to citizenship for some of the 11 million undocumented immigrants in the U.S.

So as the candidates prepare for their third debate, on the campus of the University of Colorado in Boulder, Latino advocates are making preparations of their own. None are aimed to help the candidates’ cause.

Mi Familia Vota, the Latino Victory Project and more than 60 state and local politicians and immigration reform advocates are mobilizing and organizing rallies and press conferences on the campus before the debate. Their call: Stand against anti-immigrant rhetoric.

Even Hispanic conservatives are uniting to send a warning to the Republican Party and candidates such as Donald Trump, who suggested that undocumented immigrants from Mexico are criminals and rapists. Texas Sen. Ted Cruz is also in their sights because he did not condemn Trump’s comment and instead gave him credit for bringing up the issue of immigration. Trump and Cruz want to toughen border enforcement and end automatic citizenship for babies born in the U.S. — both sore points for the Latino electorate.

GOP candidates Florida Sen. Marco Rubio and former Florida Gov. Jeb Bush, both with strong ties to their crucial state’s large Hispanic electorate, may stand a better chance of capturing Latino Republicans.

Latino conservatives plan to meet in Boulder on Tuesday to warn that the Republican Party cannot move forward without Hispanic support. And it won’t get that backing if the GOP ignores them or insults them.

A predebate press conference will send the Republican contenders a warning that there’s little chance of winning the state’s Latino vote if they fail to champion the interests of the immigrant community.

“Latino immigrants are a good punching bag,” said Arturo Vargas, the executive director of the National Association of Latino Elected and Appointed Officials Educational Fund. “I don’t think, in all candor, [GOP candidates] are even making an appeal to Latino voters at this point … They’re playing to the extreme. They’re playing to the primary base.”

That could turn out to be a costly mistake for presidential hopefuls.

Recent research by Latino Decisions, a leading Latino political opinion research firm, showed that candidates will need even more Hispanic votes this presidential election because the Latino electorate is growing — 13.1 million Latino voters in 2016, versus 11.2 million in 2012.

The number of eligible Latino voters is soaring as more U.S.-born Hispanics turn 18. That number is expected to rise from a record 24 million in 2012 to 27 million next year, according to Mark Hugo Lopez, the director of Hispanic research at the Pew Research Center in Washington, D.C.

In 2012, Republican nominee Mitt Romney won the support of about a quarter of Latino voters. In 2016 “the Republican presidential candidate will need twice that support to win the White House,” according to Latino Decisions.

The threshold of Latino support to ensure a win nationally has gone up, from 40 percent to 47 percent, according to calculations that take into account a slight drop in the black vote that surged during President Barack Obama’s run.

There are four states with a Hispanic vote of 10 percent or more — Nevada, Colorado, New Mexico and Florida — where Republicans would need 42 percent to 47 percent of the Latino vote to win. Two others, Virginia and Ohio, have significant fast-growing Hispanic populations.

Latino advocacy groups are intensifying voter registration drives, a push that is likely to make their votes matter even more and render it almost impossible for any presidential candidate to win without significant Hispanic votes. Groups know the power they potentially yield and are using every chance they get to remind candidates through campaigns and demonstrations.

Protesters disrupted a Trump speech in Miami last weekend and were dragged out of the rally.

“Right now, it looks like the GOP is not engaging the Latino community in serious issues that are important to us,” said Carla Castedo, the Colorado director for Mi Familia Vota, a national nonprofit organization that promotes Latino civic participation.

Latinos care about immigration reform, raising the minimum wage, access to health care and respecting women, she said.

“Something that is clear to us is that some candidates are not ready to represent Latinos,” she said.

And if they’re not, they may get a resounding rebuke at the polls in November 2016.