A recent National Journal article says that Latinos in Iowa can't be bothered to caucus, unless the two major parties beg them:

Iowa Latinos left high and dry by presidential candidates https://t.co/dkrmnzdAmk pic.twitter.com/jJsrZYFxrE — National Journal (@nationaljournal) January 21, 2016

Latinos just aren't that into American politics—they don't come from a tradition of participatory democracy, and they're not very patriotic.

Iowa Latinos Left High and Dry by Presidential Candidates Campaigns won’t spend real resources on Latinos in Iowa until they show up to caucus. But they won’t caucus until campaigns reach out to them. By Matt Vasilogambros January 21, 2016 DES MOINES, Iowa—Three Democratic presidential campaign surrogates bicker in front of a group of skeptical young Latino voters, some leaning back and crossing their arms in this church basement. Gabriela Domenzain, a senior adviser for Martin O’Malley, calls Bernie Sanders’ immigration plan an “imitation.” “I can say it’s not an imitation,” snaps Erika Andiola, the national Latinx press secretary for Sanders. Rep. Xavier Becerra, representing Hillary Clinton, quickly counters, “In my fights for immigration reform, Bernie Sanders was not in the room.” The room has heard enough from the three reps. Hector Salamanca, one of the leaders for local advocacy group DREAM Iowa, speaks up. “Why am I going to reach out and help these campaigns if they’re not going to invest in infrastructure, not going to invest in resources and education?” he says to the roundtable gathered at Trinity United Methodist Church this month, organized by the Latino Victory Project. “They make a lot of grand promises, but for us here in Iowa we care about the stuff that happens after the caucus, after the election.” The surrogates go quiet, if only for a moment. “You’re absolutely right,” says Domenzain. “Campaigns only come around every four years and it’s unfortunate.” Latinos don’t have a strong history of caucusing in Iowa. Of the 50,000 registered Latino voters, only 3,500 caucused in 2008—the most Latinos who have ever caucused, yet still a poor representation for Iowa’s fastest-growing population that makes up 5.6 percent of the state, according to 2010 Census numbers. [More]

Right, that's because caucusing, like voting in primaries or knocking on doors for your candidate, is a voluntary activity, usually undertaken for reasons of patriotism and good citizenship. And Latino voters, whether naturalized immigrants, or children of immigrants, do not suffer much from patriotism and good citizenship.

That's not just me saying that—that's shown by the figures above, and often heard in Latino reconquista rhetoric. As a result, Latino registered voters are less likely to bother to vote at all. See Steve Sailer's Hispanic Electoral Tsunami Postponed Once Again Due to Lack of Interest.

So why do Republicans keep worrying about the Hispanic vote?