MANCHESTER, N.H. - For months now the Republican presidential candidates, save one, have mostly ignored Hispanic voters. But that might all be about to change as the campaign now heads south and west.

With voting in Iowa and New Hampshire in the rear view mirror, the focus of the political world shifts toward South Carolina, Florida and, in early February, Nevada. Because there are more Latinos in South Carolina - 235,000 - than in Iowa and New Hampshire combined - 151,000 and 36,000, respectively - the tenor of the Republican hopefuls toward Latinos might shift, too.

From the Palmetto State, the campaign then moves on to two states with far larger Hispanic populations: Florida, where 22.5 percent of the state is Latino, and Nevada, where more than a quarter of the state is Latino: 26.5 percent.

"Definitely, they have to pay attention to Hispanics because the subject of immigration has already come up. That's a fact," said Carlos Gonzalez, a New Hampshire state representative. "Once our candidate Mitt Romney started to talk about his Mexican heritage, his family, that's an indication that there's no turning around. The issue of immigration, along with the economy, will be one of the main issues in the upcoming election."

"The candidates will have to include all segments of the population, but especially Hispanics. To date, they have not been addressed head on, but that will change," added Gonzalez, the state's first Hispanic elected official.

With the Latino vote now becoming so crucial - not just in the GOP primary but to a far greater extent in the general election - the Republican candidates could benefit from wooing the nation's fastest-growing voting bloc. More than half the growth in the country's total population between 2000 and 2010 was because of the massive increase in the Hispanic population.

Of the GOP candidates, only Newt Gingrich has made much of an effort thus far to court the Latino vote. The former House Speaker has outlined the most moderate immigration stance of all the candidates, saying at a debate in Washington, D.C., in November that the government should not expel immigrants if they have put down roots here: for instance, if they have been here for a quarter of a century, raising a family, paying taxes and obeying the law.

While Gingrich does not think those undocumented immigrants should be granted full citizenship, he does think they should get legal status.

In New Hampshire on Sunday, Gingrich even held a town hall for Latinos at a Mexican restaurant in the state capital of Manchester. "We have to end the period of having people in the shadows," Gingrich said. "It's bad for the country, it's bad for the people, it leads them to get excluded, it is dangerous. It means those that need help are afraid to show up and ask for it. So I want to find a path that gets us to a system where four or five years from now 99.99 percent of everybody in the United States is here legally and we're comfortable with it."

He warned, however, "We are not going to go into those churches and those neighborhoods and tear apart those families. The American people aren't heartless."

Gingrich's Republican rivals have voiced far more conservative approaches to the controversial issue. Front-runner Mitt Romney - who won Iowa and New Hampshire and leads the polls in South Carolina and Florida - has said that if elected he would veto the DREAM Act, a bill that would provide a path to citizenship for some undocumented children of immigrants who attend college or serve in the military.

Romney last year said that one of the greatest weaknesses of his party was its inability to woo Latino voters, who lean strongly toward Democrats. In a general election battle against President Obama, Romney noted, the Latino vote could prove crucial.  

"I need to get 50.1 percent of Americans behind me and perhaps one of the best tests is to get people like Latino Americans and say how can I convince more Latino Americans to say support a Republican. If I can do that, then I'll be doing well pretty broadly," Romney said this week.

Romney today released a Spanish-language ad in Florida, hoping to earn support in the Hispanic-heavy state. But the same day Romney also announced the endorsement of Kris Kobach, the Kansas secretary of state who helped compose the controversial immigration laws passed in Arizona and Alabama.

With many Latinos frustrated with President Obama's inability to make any progress on the immigration front, there might be an opening for Republicans to convince left-leaning Latinos to consider a GOP candidate for the White House. Selma Lopez, a New Hampshire resident set to vote for the first time in the general election later this year, said in an interview in Spanish that she believed Obama would do more than he has.

"What I see is that he has not had the type of leadership that we hoped for," Lopez said. "I feel like he's lacked a little bit of strength."

But as an indication of how Republican candidates have yet to give disillusioned Latino voters such as Lopez a good enough alternative to Obama, Lopez's husband Esteban - also set to vote for the first time this fall - voiced disappointment with Romney's immigration stance.

"I work in education and I know first-hand how important the DREAM Act is for Latino youth, for kids who are in this country without having taken part in the decision to come here," Esteban Lopez said. "The short answer is I wouldn't vote for Romney."

In Iowa last week, Jose Zacarias, another Latino disillusioned with Obama's work in Washington, said he would not even consider any of the GOP hopefuls because of their immigration stances.

"I don't think any Hispanic in his right mind is going to vote for Rick Perry or Romney," Zacarias said with a chuckle. "It might be a tough sell [for Obama], but I think the GOP is helping a lot by putting these guys forward. Romney, Rick Perry, Newt [Gingrich] for Christ's sake, you know?"

Gingrich, though, has earned praise from numerous Latinos from Iowa to New Hampshire for his immigration policy. "Newt is the only candidate who has had the courage to open the door to the issue of immigration like he did in the debates," said German Ortiz, a Republican voter in Manchester.

Members of Gingrich's campaign - such as his daughter, Kathy Lubbers, who lives in the Latino hotbed of Miami - believes that the fortunes of her father's bid for the nomination could change with the primaries of South Carolina, Florida and Nevada in the coming weeks.

"He has been working with and including the Hispanic community for seven, eight years," Lubbers said in an interview after her father's town hall in Manchester. "We have had a Hispanic person leading the charge for us for multiple years on a variety of topics even before we were involved with this presidential campaign. We have a lot of people in place, probably more than any other candidate. So I'm hopeful that it actually comes to fruition and we'll just have to see if it plays the way we're hoping it does."

  Matthew Jaffe is covering the 2012 campaign for ABC News and Univision.