Pedestrians pass by the D.C. restaurant Jaleo, which closed on Feb. 16 for the "Day Without Immigrants." (AFP/Getty/Mandel Ngan)

Sergio Roblero didn't need to imagine a “day without immigrants.” On Oct. 18 of last year, the 19-year-old line cook lived it.

At the time, Roblero -- who is from Chiapas, Mexico — was cooking at a popular Mexican restaurant called Agave in downtown Buffalo. He had overstayed a work visa by several months, he said, but he felt confident that, if he kept his head down, nothing would come of it. But early on the morning of Oct. 18, Immigration and Customs Enforcement raided not only Agave, but three sister establishments.

All told, 25 people, including Roblero, were arrested. And of the restaurants targeted in the raid, only one has since reopened.

“Immigrants are part of the U.S. economy,” Roblero said, in Spanish, via Facebook Messenger. “Now I’m under house arrest. I haven’t left to see any of my coworkers, the restaurant is closed and I can’t work.”

Thus far, few restaurants have suffered the scale of the raids that Agave did. But in cities across America, restaurants, bars and hotels are bracing themselves for the possibility of further enforcement action under the Trump administration. On Thursday, restaurants in several major cities — including José Andrés’s Jaleo, Oyamel and Zaytinya in D.C. -- shut down or cut service to demonstrate how much their businesses would suffer without immigrants.

Celebrity chef José Andrés, currently locked in a legal battle with President Trump, says he's supporting his immigrant employees taking off from work on Feb. 16 in protest of Trump's immigration stance. (Reuters)

It’s clear from the data that restaurants depend on undocumented workers for labor. Eleven percent of all U.S. restaurant and bar employees are undocumented immigrants, according to the Pew Research Center. At current industry employment levels, that translates to roughly 1.3 million people.

In some places, the numbers are even higher. According to Pew, there are even more undocumented immigrants working restaurant and hospitality jobs in New York, Florida and the Southwest.

“In major cities, you’re talking about a restaurant workforce that is maybe 75 percent foreign-born, and maybe 30 to 40 percent undocumented,” said Saru Jayaraman, a labor activist and the founder of the worker group Restaurant Opportunities Center United. “The restaurant industry in major cities would absolutely collapse without immigrants.”

Immigrants, particularly undocumented immigrants, aren't always visible to restaurant patrons. They tend to work in lower-level restaurant positions, often in roles that don’t involve interacting with customers. Instead, they bus tables, prep food or work the grill line, like Roblero did.

According to Pew, undocumented immigrants make up 17 percent of the nation’s busboys and 19 percent of its dishwashers. These figures are likely higher in major cities, in states with large numbers of undocumented immigrants, and in certain minority-owned “ethnic” food establishments. And they’re likely to grow even more in the future.

According to a new analysis by Bruce Grindy, the chief economist at the National Restaurant Association, the shrinking population of 16-to-24-year-old workers will further squeeze an industry that has already faced intermittent labor shortages since the end of the recession. Grindy says that restaurants will turn to foreign-born workers to make up the gap.

“Foreign-born employees,” he writes, “will be increasingly important to the restaurant industry’s ability to expand and create jobs in the years ahead.”

Given these trends, the restaurant industry has long advocated for comprehensive immigration reform — including a “clear path to legalization" for undocumented workers.

Shortly after the election of President Trump, Jayaraman's group began to hear from restaurants and restaurant workers expressing concern about the president’s immigration rhetoric. In response, she partnered with Presente.org, a Latino advocacy group, on an initiative they’re calling “Sanctuary Restaurants”; among other things, the project offers member restaurants a rapid-response legal hotline and organizing help. In exchange, restaurants publicly post a placard that declares their “sanctuary” status.  As of Feb. 16, 400 restaurants had signed up.

All of those establishments participated in Thursday’s “Day Without Immigrants,” Jayaraman said.

The national strike sought to show Americans what the dining scene would look like if immigrants, especially undocumented immigrants, could no longer participate. In D.C. at least, a number of restaurants closed their kitchens while leaving the front-of-house open. A trio of pubs owned by restaurateur John Andrade served drinks and let customers bring their own food. At Compass Rose, the entire kitchen staff, save one chef and line cook, are immigrants.

Immigrants workers and students went on strike Tuesday to show what a "Day Without Immigrants" looks like. Many restaurants, some of which are immigrant-owned, closed in solidarity with the community. (Jayne Orenstein/The Washington Post)

“The dining industry would not exist without immigrants. Period,” said Carlie Steiner, of D.C.’s Himitsu, in a statement.

Of course, not everyone agrees that the industry would collapse without undocumented immigrants, even if they play an important role presently. Dan Stein, the president of the Federation for American Immigration Reform, a group that staunchly opposes illegal immigration, argues that restaurants could adapt to a crackdown just as easily as they have adapted to other shifts in the labor market. He compares the attitude of restaurateurs who hire undocumented workers to the arguments made in favor of slavery almost 200 years ago: Both systems are exploitative, Stein said, and both claimed that any changes would cause business to suffer.

“Once abolished as a practice, businesses adjust, adopt, shift and innovate,” Stein told The Post by email. “The alternative is bankruptcy, and any well-managed business won’t go under.”

But in Buffalo, where three popular restaurants remain closed, that doesn't appear to be the case.

Of the 25 people arrested in the Oct. 18 raid, three are fighting deportation for overstaying their visas, and five are still in detention, said Brenda Valladares, an organizer for the immigrant rights group Cosecha, which has provided legal and organizational help for the employees. The owner of the restaurants, Sergio Mucino, has also been charged with harboring illegal aliens, as have two of his managers.

While Mucino declined via an associate at his remaining restaurant to comment, citing the pending charges, he previously told a reporter that his employees were “very nice people” and “hard workers” and that he felt “very bad for everything that happened.” In the aftermath of the raids, it came out that Homeland Security had targeted Mucino and his restaurants after receiving a tip from a former employee. In a statement, the agency said that “building and supporting a business through the intentional use of people not lawfully authorized to work here is a model that [Homeland Security] will not tolerate.”

That has been devastating to the families of the employees, Valladares said, particularly those with young children. Many of the families fear being split up if their relatives are deported. They're also having trouble buying food and paying rent while their primary breadwinners await immigration hearings; Cosecha is now providing for many of those needs. Only one of Mucino's restaurants, the taco joint La Divina, is open and in need of employees.

On a recent Wednesday evening, the phone at La Divina was answered by a 21-year-old college student named Drew Smith. He was hired after the raids, he said, to replace a cashier who had been arrested, along with several new cooks who, early on, didn’t even know where to source ingredients. Smith loves La Divina: The people are nice, the tacos are good, and it “feels like working in Mexico,” he said.

“But it seems like less people come to the restaurant now,” he added. “I think there’s a perception that the tacos are different.”

More from Wonkblog:

You could soon pay more money for worse food. Thanks, Donald Trump.

If someone doesn’t like immigrants, ask them this question

Why so many of America’s sushi restaurants are owned by Chinese immigrants