PHOENIX

Want to see America unraveling? Come here, to Thomas Road and 35th Street, to M. D. Pruitt’s furniture store. Come on Saturday morning and stand near the eight delivery trucks barricading the parking lot, like the wall of an urban Alamo.

For the last seven weeks, a sidewalk protest here by Latino immigrants has blossomed into a feverish reality show, attracting Minutemen, mariachis, children dancing in Mexican folk costume, white racists, United Nations observers, Phoenix police officers and Maricopa County sheriff’s deputies.

The weekly confrontation — strident and stalemated — perfectly mimics the national debate. But it’s a sideshow to something uglier: what happens when immigration’s complexities are handed to local law enforcers sympathetic to the fury of one side.

Thomas Road has lots of Latino day laborers, or jornaleros, who hustle for work near Home Depot. A few months ago, the Phoenix police shooed them away. They dispersed to streets nearby, angering local businesses. One of the biggest, Pruitt’s, hired off-duty city police officers to keep jornaleros at bay. The city put a stop to that, so Pruitt’s turned to the county sheriff, Joe Arpaio.

Sheriff Joe, as he is known, needed no prodding: hunting undocumented immigrants is his specialty. He has arrested hundreds under a state antismuggling law (for smuggling themselves) and has had 160 officers deputized as federal immigration agents. They have made more than 50 arrests near Pruitt’s since the protests began.

They’ll pull a car over for a traffic infraction, then check everyone’s papers. They say they act on reasonable suspicion only — if they see a shirt or shoes like those worn south of the border or hear Spanish. They say it isn’t profiling.

There is no doubt whose side Sheriff Joe is on. He has officers on Pruitt’s payroll, guarding the lot on protest days. Last week, he issued a news release demanding that the demonstrators stop hurting Pruitt’s and vowing to crank up the pressure until they went away. It was a naked attempt to stifle dissent and help a business ally.

People here are used to that from Sheriff Joe. He describes himself as “America’s meanest sheriff” and has recently been basking in the love of nativists like the Minuteman Chris Simcox and radio host Terry Anderson, who gushed over him at a roast in Sun City West this month.

If Arizona begins punishing companies that hire illegal workers under a law that takes effect Jan. 1 — a lawsuit to block it was thrown out Friday — it will fall to counties to do the purge. In Maricopa, that means Sheriff Joe.

The protests at Pruitt’s are the only real opposition he has faced. Their leader is Salvador Reza, a stocky American of Mexican and Apache ancestry, an Air Force veteran who has spent years organizing jornaleros and small-business owners here.

Mr. Reza says he can’t understand why America accepts global flows of companies, money and jobs but not workers. Why faith in market forces seems to have been eclipsed by fear of immigrants. Or why the country cannot set up legal channels to let jornaleros come and go and not be hassled.“They actually are people with a work ethic that would make the Puritans proud,” he said.

Pruitt’s owner, Roger Sensing, says he needs armed officers to protect customers from jornaleros. Mr. Reza calls that ridiculous, and one informed noncombatant, the Rev. Craig Geiger, pastor of a Lutheran church across the street, agrees. He told me he had never seen a laborer enter Pruitt’s lot. He also said his Latino congregation did not drive to church anymore. Documented or not, they fear Sheriff Joe. They walk.

Pastor Geiger leaves the neighborhood on Saturdays, because it gets deafening. When I was there, a trio singing Mexican ballads strolled through the crush. A Minuteman with a bullhorn followed them. “Monkeys coming through!” he shouted. His side rushed up to drown the music out: “Born in the U.S.A.! Born in the U.S.A.! K.K.K.! Viva la Migra! January First!”

The restrictionists see Jan. 1 as the dawn of a new era, when the Mexicans disappear and everything gets pure and legal again. It is uncertain whether Arizona’s economy will survive the exodus. “Unfortunately, they’ll probably wake up when they bankrupt the state,” Mr. Reza told me.

For a slide show and further commentary on what’s happening in Phoenix, go to nytimes.com/opinion.