DES MOINES — At La Favorita, a Mexican grocery store here, there is plenty of food for sale — and also a new brand of politics.

A handwritten sign, hanging over the door, proclaims in Spanish: “Wake up! Register to vote! It is the hour to unite and change our future, the future of our children — and the future of this country!”

And every weekend, at a small table behind the newspapers and a case of cold sodas, a trickle of newly minted citizens are doing just that — not in numbers large enough to constitute a voting bloc, but enough to make politicians take notice.

The effort reflects the growing presence of Hispanics here in Iowa, posing a challenge to Democrats who are eager to court a new interest group but wary of offending conservative white voters concerned about immigrants flowing into their state.

At campaign stops, Democratic candidates are frequently asked, often in hostile tones, what they are going to do about the influx of immigrants, mainly from Mexico and Central America, that are streaming into Iowa and changing the culture, and potentially, the political landscape of this early nominating state.

For Democrats, the situation in Iowa could be a harbinger for other states, as rural America deals with a flow of immigrants that other places, like Florida, New York and California, have already experienced.

“Democratic strategists know that the Latino vote is their future,” said Hector Avalos, a professor and founder of the U.S. Latino Studies program at Iowa State University. “But they are having to handle this with kid gloves. They don’t want to anger native Iowans. But they know that there could potentially be millions of new voters nationwide. Democrats are sort of treading lightly, and trying to appease both sides.”

To varying degrees, Democratic presidential candidates are reaching out to Latino voters here. Many have set up Hispanic steering committees, sent bilingual workers to Hispanic events and sponsored visits from Hispanic politicians. Senator Barack Obama of Illinois brought Federico Peña, the former Denver mayor and national Obama campaign co-chairman, to Iowa, while the Clinton campaign played host to a visit from Senator Robert Menendez of New Jersey, who is Cuban-American.

But no campaign is reaching out too far. Most Democrats steer clear of the immigration issue unless it is raised by voters at campaign events. Most Democratic candidates supported the failed Kennedy-McCain bill in Congress, which would have provided a path to citizenship for illegal immigrants.. Yet they talk tough on border security.

“Democrats running for office could take leadership on the issue of immigration reform,” said Alex Orozco, an organizer with United for the Dignity and Safety of Immigrants. “But they are not. I don’t sense that the Democrats think immigration is a priority for them, not even close. When they do talk, they are often very good at talking more about enforcement because if they talk positively, they open themselves up to attack. The Republicans care more about this issue — but in a negative way.”

Iowa, like other parts of the nation, is in the midst of change as more Spanish-speaking immigrants move into the state, taking jobs in meatpacking, corn and egg processing plants. Evidence of their growing presence comes in the form of new Spanish-language newspapers, radio shows and mom-and-pop stores in fading downtown areas.

At the moment, an estimated 114,700 Latinos are in Iowa, a 28 percent increase since 2000, according to the Iowa Division of Latino Affairs. In some small towns, nearly a third of the citizens are Hispanic, although about half the Hispanic population is concentrated in five Iowa cities, including Des Moines.

Hispanics are the fastest-growing ethnic group, but still represent just 3.8 percent of Iowa’s population. By most calculations, there are some 37,000 registered Hispanic voters in the state.

Yet, as the population has grown, so have concerns. A Hawkeye poll conducted by the University of Iowa in August showed that immigration was a “very important” issue to 43 percent of Democrats and 58 percent of Republicans. Those polled had a broad range of ideas about what should be done, from those who supported efforts to make illegal immigrants citizens to those who favored mass deportations. On top of that, a series of highly publicized workplace raids at meatpacking and other plants here have heightened emotions on all sides.

Latino leaders like Bernard Ortiz, who came to Iowa 30 years ago and is the Latino outreach organizer for the Service Employees International Union, has made it a mission to register Hispanic voters. Each weekend, he goes to La Favorita, Mexican rodeos or local soccer games that attract immigrant families to sign up new voters and explain the caucus process.

“Republicans in Iowa have made a big effort to use us as a scare tactic,” Mr. Ortiz said in an interview. “And that works well for a good percentage of Iowans. The Democratic contenders are doing a good job of addressing Latino issues outside of Iowa but are fearful of losing voters here. Both think we are irrelevant to the process. But we are in the process of registering to show that we are not irrelevant.”

Many new citizens avoid anything to do with the government, given the recent workplace raids. Others come from countries with a history of corruption and fear their vote is irrelevant.

“Lots of new citizens come here with an old country mentality,” Mr. Ortiz said. “They feel their vote doesn’t matter and the rich always win.”

Gricelda Ramirez, whose father, Ignacio, owns La Favorita, said a combination of fear and apathy was hurting voter registration efforts. In addition, the caucus process, in which voters must appear before their neighbors and speak up about their political choices, can be intimidating for those for whom English is a second language.

“A lot of people are scared to get involved because they think that immigration will come for them,” Ms. Ramirez said. “Even though they have become citizens, they don’t know where to vote or what it is all about.”

By most accounts, Hispanic leaders here say that among the Democrats the Obama campaign has been the most aggressive in reaching out to them.

“We are reaching out to nontraditional people,” said Joan Kato, head of Hispanic outreach for the Obama campaign. “We can’t expect the voters to come to us, so we are going to them and showing up at events to build trust.”

The Obama campaign has sent Ms. Kato and her crew to over 50 Latino events in the state, is lining up Spanish-speaking supporters to work on caucus night, has printed literature in Spanish and English explaining the caucus process and has a Latino steering committee in every region of the state.

“We’ve been heavily courted by Obama,” said Dawn Martinez Oropeza, an activist with the Iowa Allies for Immigration Reform. “Obama has been the only one there right from the beginning — we’ve gotten V.I.P. tickets to events, he’s been on conference calls with Latino leaders and they’ve always had booths at Latino events. He’s tried to make a more personal connection with the community. From the others, we’ve gotten no invitations to anything.”

Jesus Estrada, Latino outreach coordinator for the Iowa Democratic Party, said Latinos were a natural constituency for the Democrats. But he, too, is aware of the challenges.

“Our biggest problem is to get people to understand the process,” said Mr. Estrada, whose father is from Venezuela. “Many don’t have a clue, and we need to relate politics to their everyday lives. We’re targeting the audience, and we are getting the message out.”