When Taquería Frontera opened last summer in Cypress Park, I walked in with my baby tied to my chest and ate on my feet, swaying, hoping she wouldn’t wake as I tried a taco al pastor.

The tortilla was gently toasted in the crimson fat that dripped from the vertical spit. Still pliable, still intact, it held thinly sliced pork, lavishly spiced, frizzled to a crisp at its very edges, and the finest rubble of onion and cilantro. Then, it deviated slightly from the local archetype.

Two salsas with competing interests moved through it — one creamy, white and mellow; one theatrically, radiantly hot — and they mixed in places, animating each bite a little differently. The baby wiggled, but it didn’t matter. I was back at the register for more.

Every day, there’s an ebb and flow of movement across the border with Mexico as Tijuana remakes the appetites of Los Angeles, shaping its tastes from 130 miles away. When Tijuana-style birria de res took off a few years ago, it owned the algorithms, hyping demand for birria while reshaping its perception. And at Tijuana-style taquerias across Los Angeles, trompos spin and smoke billows, carrying the scent of carne asada.

Frontera doesn’t have the efficiency of Tire Shop Taquería, or the geographic reach of Angel’s, or the camera-ready showmanship of Villa’s Tacos, but its tacos have finesse, consistency and an unmistakable house style.

The story of Taquería Frontera starts at Tijuanazo, the Tijuana chain once known as Taco Nazo. That’s where Juan Carlos Guerra, who was born in Los Angeles, studied under his father, Antonio Esquivel. “My salsas are very good, but then I taste his and — what am I missing?” said Mr. Guerra, who opened Frontera last summer. “I feel like I’m always chasing him!”

All of the tacos at Frontera are compact but abundant, thoroughly seasoned with nuanced and vivid salsas. They come half-wrapped in paper, nestled in red plastic baskets, each type coddled and proportioned a little differently, according to its specific needs (ordering isn’t an opportunity for customization and there’s no salsa bar to plunder).

The pastor is built with corn tortillas from El Grano de Oro, imported each week from Tijuana, which is structurally sound and can withstand a little toasting, while the deeply seasoned carne asada and chorizo sit happily in the more delicate, freshly pressed tortillas that come hot off the restaurant’s comal.

Taquería Frontera is still new to the Los Angeles taco scene, but within months of opening it won the championship title at Birriamania, an annual competition held by the local food and news site L.A. Taco. Their taco al pastor soon placed first on the publication’s annual taco list.

So much recognition, so fast, could wreck a place that’s not prepared for the tourists, influencers, and “30 tacos to go” guys who inevitably start to show up. But Mr. Guerra was already building his staff up from five to 20. He’d hired a few star tromperos, tortilleras and runners from his father’s restaurants in Tijuana to come over and train new cooks for a few months.

Mr. Guerra was ready to open a second location when the Trump administration’s immigration raids cracked down in Los Angeles. It didn’t seem like the right moment to celebrate a grand opening.

Nearly 3,000 people have been arrested since June, many grabbed by masked, armed agents and officers in violent and chaotic scenes documented by passers-by with their phones. Agents and officers have targeted carwashes, store parking lots, parks and other public spaces where food vendors, in particular, are vulnerable. Images of abandoned ice cream stands and grills are chilling because of what you don’t see — the people missing from the scene.

Restaurant owners had been steeling themselves since January, calling up immigration lawyers, handing out red cards that detail rights and protections, and preparing for agents to come knocking at their doors. But regardless of their status, people across the city don’t feel safe, which means Latino-run businesses, particularly in Latino neighborhoods, are quieter than usual and so many food vendors still haven’t returned to their usual spots.

It might be possible to measure the economic toll on the city, but how do you quantify the rest of it?

Everyone knows that immigrant labor powers restaurants across the country, but immigrants are more than their labor. And as the raids drag on, people across Los Angeles are doing the work of caring for each other in overlapping, unofficial networks — they deliver groceries and meals, they drive each other's children to school, they send alerts through group texts and on WhatsApp — so that day-to-day life can go on as much as possible.

During the week, Taquería Frontera feeds neon-vested workers from the bus depot down the street, preschool teachers, plumbers and landscapers, women in pantsuits gripping laptops, men in paint-smeared jeans and boots getting their orders to go, teens with skateboards, and the staff from the nearby auto shop with pens clipped to their pockets.

Frontera has a red and yellow sign that stretches across its roofline, a sign you must walk under to order your food, a sign you can’t possibly ignore: “More tacos, less borders.”

As I passed under it again last week, I thought about how this Tijuana-style taco, at less than $4, is one of the smallest and most satisfying units of pleasure in Los Angeles. How on a work day, during the lunch rush, a kitchen full of people devoted to its excellence make a taqueria feel like someplace sacred.

A year since it was put up, that sign reads differently to me, with more distress and defiance, with more urgency, too. It reads like a prayer.

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