Here comes a troupe of mariachis, trying and failing to creep stealthily up the walk to a little house in a lost corner of Dumfries, Va. It's a quarter past midnight and 10 degrees. Forgive them for being an hour late — they've been speeding from one gig to another all evening. Their mere arrival makes the neighborhood begin to seem not quite so frozen and silent. Is it the bravura of the tailored jackets, big-shouldered and so white they almost glow in the gloom? The sparkle and jangle of the silver-buttoned ornaments that run up the hems of their tight black pants? The gleam of their patent-leather boots?

They tune their instruments on the fly as they reach the house. Pum pum, goes the guitarrón searching for its bass tone. Shhhhhhhhhh, says Antonio Celis, coming out to greet them. He wants to preserve the element of surprise until the last minute for his sister’s birthday party. Just inside the front room, Celis whispers his request for the first song. “Listo!” say the mariachis: Ready!

Maria Reyna Celis, who just turned 46, hears them before she sees them: A merry trumpet blast announces the melody, filling the house and probably penetrating the dreams of neighbors. The other instruments join in, and the mariachis play while marching down the stairs to the basement where the party is in swing. Maria grew up in the Mexican state of Jalisco, but for 25 years she has lived in the United States, where she works construction and has raised four children. For her, she says, this music has never lost its power to conjure the past and relieve the stress of life in America.

The first song, “En Tu Día” (“In Your Day”), is more than 60 years old.

Just a memory has remained

Of the childhood that finally passed

Let’s celebrate your happy day

Your friends, relatives and I

Maria and Antonio dance a two-step together, and soon almost everyone is dancing. “How we love you, Reyna!” the friends and family from three generations chant in Spanish. The concrete floor and walls are painted white and decorated with balloons. Chairs for a few dozen guests are pulled back along three walls, while the five musicians stand along the fourth in a classic mariachi lineup: trumpet, violin, guitar, guitarrón (a six-string bass shaped like a fat guitar) and vihuela (a five-string small guitar). The musicians share lead vocal duties and also sing as a chorus. The crowd requests tunes from deep within the bottomless well of mariachi songs — “Guadalajara,” “Caminos de Michoacán,” “Como Mexico No Hay Dos” — and know them well enough to belt out every lyric.

Scenes like this play out all over the Washington area on weekends, and not just in Latino homes. For some time, mariachis have been the life of many D.C. parties. The late Sen. Edward Kennedy, for instance, used to invite mariachis to gatherings, where he would sing “¡Ay, Jalisco, No Te Rajes!” and tell stories of his brother Bobby and the farmworkers.

On this Saturday night, I’m following Mariachi Nacional de D.C., led by Pepe Gomez, 34, one of the busiest mariachis in town. That’s him with the cropped hair and dimpled cheeks, grinning with unfeigned ecstasy as he sings “El Mariachi Loco” and frantically strums his vihuela. Tonight he and his colleagues will log 200 miles crisscrossing the area to five gigs, and that’s considered a slow night in the fallow season between New Year’s Eve and Cinco de Mayo.

As we make the rounds, I can’t help thinking how, for these gatherings of Latinos, more than music is in the air. Earlier on this Saturday, as the mariachis were pulling out their suits, President Trump returned to the subject of his wall that Mexico supposedly will pay for. Either he gets the wall, he told reporters, or else the “dreamers” who were brought here illegally as children will not be able to stay. Trump’s drumbeat of antipathy toward immigrants also includes canceling protected status for tens of thousands of Central Americans and seeking to curtail legal immigration for family members. I don’t know if anyone at this party is undocumented or a dreamer, but the Salvadoran violin player, for one, is bracing for the news that will come the following week — when he will learn that after 20 years in America he will lose his protected status.

Mariachi music isn’t itself political, and in the several weeks I spent with some of the mariachis in the Washington area, musicians and audiences generally didn’t bring up politics on their own. But given the sense of siege that has settled over so many Latino communities, I felt an obligation to ask. Many people told me they consider enjoyment of this music a kind of political statement. After all, mariachi — with its brassy sound, fancy suits and, on formal occasions, ridiculously big hats — is culturally unapologetic and unbowed, the opposite of living in shadows.

“Mariachi music is a way of expressing ourselves and what we feel,” Maria Reyna Celis tells me after the mariachis have played for their allotted hour. “It makes you more proud of your roots, more proud to say, ‘Yes, I can.’ I’m here to surpass myself. And no wall is going to defeat what I came to do.”

Mariachi — which can refer to a musician, an ensemble of musicians, or the music of such an ensemble — emerged in Mexico more than a century ago from Spanish and mestizo roots. The music was closely identified with the common people, but the composers and musicians who took it up were sophisticated practitioners who brought a distinctive virtuosity to the pieces. Thanks to powerful radio stations, Mexican movie idols and immigration, it spread throughout Latin America and also found a foothold in the United States. In the early 1970s, Frito-Lay hijacked a beloved mariachi melody to sell corn chips, while mariachi music and pageantry are threaded through the recent Pixar movie "Coco," which was nominated for two Academy Awards.

Whenever mariachis are playing, requests for songs come fast and hard. The guy alone at the bar of a restaurant in Sterling, Va., asks for one that makes him stare into his drink. A woman picks another that causes her husband to cross their living room in Gaithersburg, Md., and ask her to dance on their wedding anniversary. Unlike some musicians, mariachis never get tired of playing the hits. And there are so many. Their repertoires can number more than 100. It’s a point of pride for the musicians to be able to play anything in the vast canon.

Around Washington, there are five or six groups with stable memberships, and countless musicians who are on call to help form an instant mariachi when another freelancer lands a gig. Gomez is one of the most active bandleaders. His Mariachi Nacional is one of few groups in the Washington area trying to earn a full-time living.

Gomez was a self-taught guitar player and singer dabbling in various styles before he discovered mariachi. His mother, Diana Millán Hernández, told me that she and his stepfather, who was also a musician, appreciated her son’s passion for music because no other subjects in school or alternative careers seemed to interest him as much.

After moving from Acapulco to Cancun as a teenager, Gomez saw mariachis at work. He liked the way they looked and the effect the music had on people. “You can intensify emotions,” he told me in Spanish. “If the people are unhappy, you can make them more unhappy. If they are happy, you can make them more happy.”

For his first mariachi suit, he traded his watch. As a cocky guitarist with a rich tenor, Gomez thought he would fit right in with the first group he talked his way into. Instead, he got fired after his first performance; he found the music deceptively difficult, he told me. That setback, though, only deepened his resolve. He said he tried to learn at least one new song a day and also took up the vihuela. He started playing with more accomplished ensembles and relished the flexibility of mariachi to absorb a range of musical expressions, from boleros, cumbias, rancheras and sones to pop ballads and classical passages. But his devotion to mariachi over other styles of music was, in part, a practical calculation. An older musician had counseled him that he would always find work because mariachi would never go out of style, and “in whatever part of the world, people are going to recognize the mariachi.” Gomez has found it to be so: “They may not know me in person, but when I go dressed as a mariachi, they know who I am.”

Gomez moved to the Washington area about 10 years ago and started playing music. He also came up with an ambitious model for the mariachi trade. He brings several Mexican musicians and folk dancers at a time to the area on work visas for cultural specialists, and they live together in a mariachi group house. Gomez’s dream is to collaborate with local schools, cultural institutions or private sponsors to provide mariachi workshops, with an eye toward eventually opening a mariachi school. “What I want to do is teach people what is my culture, my original roots,” he says. “This music has crossed borders and made many changes in lives.”

He has succeeded in raising the local level of mariachi musicianship a notch by importing so many skilled players, some of whom had experience working in respected Mexican ensembles. However, his efforts to establish the workshops haven’t panned out, and some of the artists have returned to Mexico bitterly disappointed that his project wasn’t better organized. In November, Gomez had enough musicians to entertain two parties or restaurants at once. By January, he had to dip into the pool of freelancers to fill out his ensemble. He says he is not giving up, and the next group of 11 or so musicians is supposed to arrive by springtime.

“There’s a making-a-buck side and there’s the sounding-really-good side,” says Daniel Sheehy, co-founder of the longest continually playing mariachi ensemble in Washington, Mariachi Los Amigos. “He tries to split the difference by trying to bring in really good musicians who sometimes get disenchanted.”

One of the local musicians Gomez has recruited to sit in with Mariachi Nacional in recent months is Humberto Quiñonez, a trumpet player of Colombian heritage. “He’s very demanding,” Quiñonez says of Gomez. “He thinks that all this music, if you don’t know it, you have to study it, learn it.”

When Gomez is singing and playing his vihuela for a passionate crowd that is dancing and singing along with him, he seems possessed by a kind of rapture. He closes his eyes, tilts his head back, starts dancing in place and somehow enunciates the words through the widest smile. He looks like an illustration for a line in a much-requested tune: El mariachi loco quiere bailar (The crazy mariachi wants to dance).

Yet the happy demeanor is a mask for the tension of trying to make a living out of what he loves — a tension part-time mariachis don’t feel as keenly. All are imbued with the higher purpose of this music, but they’re not all trying to pay the rent with mariachi.

That conflict between art and commerce is on display one Monday morning in Gomez’s house in suburban Lanham, Md. After a communal breakfast of eggs, pureed black beans and spicy nopales, the musicians of Mariachi Nacional settle in the living room for a rehearsal. Gomez sits on the couch with his vihuela. On the wall is a crucifix and a certificate of appreciation from the White House for playing there during National Hispanic Heritage Month a few years ago. They’re practicing for a concert being held at the Palace club in Woodbridge, Va., in just a few days. They’ve been hired to accompany a Miami-based singer who is on a national tour presenting an homage to the late Mexican crooner Juan Gabriel. Gabriel was known for his anthemic tear-jerkers and love songs; the touring tribute singer, Carlos Daniels, does a skillful impression.

Standing in the center of the living room, with his hair pulled back in a ponytail and his face strafed with emotion, Daniels pours himself into Gabriel’s ballads. He sings in a higher key and has a slightly different approach to some songs. Gomez takes notes on the changes, but some of the other musicians start muttering. They know the standard arrangements, especially one of the violinists, who happens to have played in Gabriel’s ensemble. After 90 minutes, they’ve barely made it through half of the songs in the program. Gomez calls a halt. He and Daniels go out on the back deck for a private chat. Gomez tells Daniels that one rehearsal isn’t enough for what Daniels is asking. He won’t let the musicians go on stage if they won’t be at their best, but the mariachis can’t spare the time for another rehearsal unless they’ll be paid.

Daniels storms back into the living room raising his voice theatrically in Spanish. He’s never been treated this way, he says. “Mariachis play for love, not money!”

Gomez winces at the dig. The two men argue back and forth, while the musicians stare impassively. Daniels thinks the mariachis should have done their homework on their own time and been better prepared. Gomez retorts that Daniels has canceled at least one previous show without warning. How could they have been sure the same wouldn’t happen this time?

Gomez asks Daniels to leave. “I’m going to cancel the show,” Daniels declares as he packs up his things. (Actually, it takes him less than a day to recruit another mariachi group.) After Daniels is gone, Gomez says, “That’s part of being a mariachi.”

Because of the way mariachi evolved to accompany moments of celebration and sorrow, the lyrics rarely make overt societal commentaries. But as with all art, context matters. "People give music meaning in the situation," Daniel Sheehy tells me. In addition to playing trumpet for Mariachi Los Amigos, he is an ethnomusicologist and author of the book "Mariachi Music in America: Experiencing Music, Expressing Culture." "Ever since the 1960s, with the Chicano civil rights movement, just putting a mariachi up there and saying, 'This is us, this is great,' can be a form of resistance. It's resistance along with pride and social coherence. It doesn't necessarily have to be a literal song."

Sheehy started playing mariachi music as a student at UCLA in the late 1960s, and in 1978 he co-founded Mariachi Los Amigos. As a scholar and former director of Smithsonian Folkways Recordings, he argues that wherever mariachi has gone, and perhaps most especially in the United States, a secret to its vitality is its knack for being useful amid changing times. It’s more than party music. Over the years, Sheehy has played at funerals, baptisms, Catholic Masses, weddings, serenades — any of what he calls “those peak moments in people’s lives.”

When mariachi songs aren’t about small triumphs over circumstances, they are often about carrying on despite setbacks. The mariachi ethos is summed up in one of the most-sung lines — Ay ay ay ay, Sing and don’t cry — which, of course, implies there’s something to cry about.

In my time following mariachis, I find that old hits are resonating with new layers of meaning. One Sunday afternoon at the restaurant El Molcajete Moya in Woodbridge, a group called Mariachi Arriero is playing a popular tune from the late 1970s called “La de la Mochila Azul” (“The Girl With the Blue Backpack”). It’s about a boy who misses a girl after she suddenly disappears from school. The wistful lyrics — originally suggested to be about family strife in a film by the same name — lend themselves to another interpretation now. Was the girl’s family deported back to Mexico?

On a Wednesday evening at Los Toltecos restaurant in Sterling, Emily Vasquez is celebrating the 4th birthday of her daughter, Kimberly. After Mariachi Nacional (minus Gomez; he was singing with Mariachi Nacional’s folk dancers at a different restaurant) plays two decidedly apolitical songs — “Happy Birthday” and “Hermoso Cariño” (“Beautiful Darling”) — I ask Vasquez if this music carries extra significance amid the harsh rhetoric about immigrants. “The music has definitely meant more this year than it has ever meant in the past,” she says. “That’s how we stick together — music.”

At another table, Angel Hernandez and Maria Ramos are dining with their three children. They request a classic, “Mujeres Divinas” (“Divine Women”). Ramos asks for “Acá Entre Nos” (“Here Between Us”) because it reminds her of her mother. Hernandez requests a special piece, “Ya Me Voy Para Siempre” (“I’m Going Away Forever”).

The lyrics are about a lover going away because his beloved doesn’t love him anymore. But the song has taken on a different meaning for Hernandez and Ramos. When Hernandez came from El Salvador to the United States two decades ago, he had to leave behind Ramos, then his fiancee. During their separation, he thought of that song a lot. She joined him after two years; they got married, had children and built a life. Even though they went away from El Salvador forever, the song can bring them back. “The politics is quite intense right now,” Hernandez says in Spanish when I ask him about it. “Mariachi culture is something that doesn’t tarnish, that politics can’t damage. This culture is forever.”

The following Sunday evening, Gomez and Mariachi Nacional are offering songs from table to table at Señor Tequila’s restaurant in Germantown, Md. Olman Díaz from Honduras makes a point of asking for “Los Mandados” (“The Errand Runners”). It’s the picaresque tale of a determined undocumented Mexican immigrant who never gives up trying to cross the border. After singing along, Marisol Guevara, who is from El Salvador and is married to Díaz, tells me why they picked the song: “Immigrants are not a threat but a value to this country. We are the strong hand this country needs.”

The Saturday-night mariachi odyssey continues to a living room in Silver Spring, Md. At the center of the singing and dancing is Ariel Ruiz, wearing a floral print dress; this is her quinceañera, a celebration of her 15th birthday.

She dances with her father. She leans her head on the shoulder of her mother, thanking her for the surprise gift of this mariachi performance, which she had first dreamed of for her quince when she was a little girl. She can sing the words to most of the songs. “It’s an opportunity for your parents to make a special moment for you, and to also embarrass you sometimes,” Ariel tells me, catching her breath. “It creates an environment where everyone’s having fun.”

I ask her father, Mario Ruiz, about the wider political environment. “It’s a shame we have to go through these difficult times,” he says. “With mariachis here, it just brings a little bit of Mexico to our home in Maryland.” Ariel was born in the United States and spends summers in Mexico. “She’s certainly Mexican,” Mario says, “but I want her to be American. You don’t forget that heritage, but you still need both.”

Standing near the most prominent decoration in the living room — a poster of the Jefferson Memorial, the Washington Monument and the other marble symbols on the Mall — the mariachis launch into “Cocula,” named after a city in the region of Mexico where mariachi was born. Ariel’s great-uncle Humberto Mercado jumps up to sing in Spanish.

From that land of Cocula

That is the soul of the mariachi

I come with my song

After the tune is finished, Mercado tells me, "When you die, they bring you mariachis. When you are born, they bring you mariachis. When you fall in love, they bring you mariachis." In between, in times of change and uncertainty, the mariachis will be there, too.

David Montgomery is a staff writer for the magazine.