MARSHALLTOWN, Iowa - At the 3 p.m. shift change Friday, compact cars rimmed with road salt and dirt rolled up to the JBS Swift meatpacking plant, ranchera and salsa music trickling from a few rolled-down windows.
Hundreds of mostly brown-skinned men walked double-time into the plant, part of the wave of Latino immigrants who, over the last two decades, have transformed this city from a traditional farming community to what could be the most diverse municipality in overwhelmingly white Iowa.
The air smelled of slaughter - and money - as semitrailers full of hogs bellied up to the loading docks.
In the week leading to Iowa's presidential caucuses, seven candidates from both parties descended on Marshalltown, about an hour northeast of Des Moines. After services at New Hope Christian Church last Sunday, the pastor and his wife handed out tip sheets listing each event and urged congregants to go.
Former Pennsylvania Sen. Rick Santorum, a Republican, held a town hall in the church auditorium that day. Later in the afternoon, retired neurosurgeon Ben Carson, briefly the front-runner in the Iowa GOP race, spoke at the Best Western Regency Inn. In quick succession last week came Republicans: Florida Sen. Marco Rubio, Donald Trump, former Arkansas Gov. Mike Huckabee, and former high-tech CEO Carly Fiorina.
Oh, and Democrat Hillary Clinton came to the middle school one night.
"It's kind of a bellwether area for both parties in the caucuses," said Grant Young, a Republican strategist in Iowa.
The blue-collar city, which has shed manufacturing jobs, epitomizes the economic squeeze of the American middle class. And Marshalltown has grappled for years with immigration, the issue that fires up conservative GOP base voters almost as much as terrorism.
Today, about a quarter of Marshalltown's population of 28,000 is Latino. By contrast, Hispanics make up about 6 percent of Iowa's population. A number of Burmese and Sudanese immigrants also have settled here.
In the 1980s the meatpacking industry mechanized production, boosting output and slashing wages. Meat processors already faced a labor shortage as the U.S. rural population shrank and fewer Americans wanted the repetitive, dangerous jobs, the industry says. Packers turned to Mexico and the rest of Latin America for workers.
"It's like they've got a sign on the border, 'Come to Marshalltown,' " said Mike Foreman, 66, who worked at the meatpacking plant until 2000, when a back injury forced him to retire.
"The company paid them less than they paid us," he said last week at the city's senior citizens center. "The way I look at it, they're taking food out of our mouths."
Some of those who came were in the country illegally. The first recruits piling into Marshalltown were single men, mostly from Mexico. Eventually they followed a common immigrant pattern, settling down and encouraging people from back home to follow them. They got married, raised families, and some built the town's 40 Latino-related small businesses.
In the Republican campaign, immigration is usually discussed in black and white terms - a matter of upholding the rule of law and protecting the national security - and the loudest voices, like Trump's, carry the farthest.
Many Anglo residents of Marshalltown, however, have nuanced views. They don't want to wall off Mexico or to round up and deport 11 million undocumented people.
"Some of the Republican stands seem heartless to me," said Jerad Hintz, 36, a Republican dentist considering Rubio at a town hall at Marshalltown Community College. "Rubio is sympathetic. He wants to control the borders, which is fine, but he comes across as much more in touch with how it is in reality."
Hintz runs a practice that specializes in treating Hispanic patients. "I have a lot of friends and family who are immigrants. It's hard for me to believe we could, or would even want to, round them up and send them all back."
Robert Silver, a student at the college, used to work at the Swift plant alongside a woman from El Salvador. Now, he's married to the woman's daughter, Heydi Menendez-Silver, who is becoming a citizen next month.
"Immigration is one of the most divisive issues there is, but I don't think there's a lot of tension in town between the groups," said Silver, 30, who works at the Lenox heating and air-conditioning plant here. "A lot of people have been personally touched, and that has changed minds."
Luis Cisneros, 41, agrees. In 1990, he arrived from Long Beach, Calif., where his mother had taken him from Mexico. Life and schools would be better in Iowa. Cisneros remembered three fellow Mexican students; locals would jostle them on the walk to class, trying to start fights to get them in trouble. "But one teacher promised and got us to and from school safely," he said.
Now, after a quarter century, he feels more at home and welcome.
"I understand that Mr. Trump is talking about throwing people out, but this town has been growing because of the Hispanics," Cisneros said. "I know some do bad things, but we do good things, too. We're here because we want to do better."
Like anywhere, though, there are still irritations, and some locals have been less welcoming than others. People say that the Latinos stick together and don't show any interest in learning English. Fearful of Mexican drug gangs, they also say that the Latinos have contributed to an increase in violent crime. (Police statistics find the crime rate is stable or declining.)
Marshalltown's leadership has worked hard at trying to get along. The police department has made a point of hiring Hispanic officers, and the force has undergone sensitivity training. Schools have a program that helps parents learn English as their children learn it.
The rumblings of partisan combat on immigration, however, are causing anxiety. Trump held a rally at the high school arena last week, where he was endorsed by Arizona Sheriff Joe Arpaio, the hero of immigration hard-liners. Latinos protested.
"Now, everybody relates us to El Chapo; he's like our flag," said Monica Huerta, 45, referring to the notorious drug lord, recently recaptured, whose gang authors so much violence in U.S. cities. Huerta came to Iowa from Ciudad Juarez in 1991 and spent four years at the packing plant scooping the stomachs and intestines from hogs.
Cisneros, who works at a wind-turbine plant in Newton, said Trump should be careful what he seeks. "If we go to Mexico, how do we get jobs?" he said, switching between English and Spanish. American-born children of the deported would not be allowed at school, because they are not citizens, he said. "There won't be just one Chapo, but a thousand of that guy."
Latino immigrants still talk about the federal raid at the Swift plant in 2006, on the feast of Our Lady of Guadalupe, a sacred day for Mexicans. Agents handcuffed those without papers as a SWAT unit prowled the roof; 96 were arrested and deported.
"Now it's talk of a wall and, 'Get out and don't come back.' " said Sister Christine Feagan, who runs the Hispanic ministry at St. Mary's Catholic Church. "These people are vulnerable."