“There are two stories,” a leader of the Rat Stabbers told me. We were filing through police lines toward the cylinder, the stadium of a powerful Buenos Aires soccer team called Racing. Inside, about 60,000 enemy fans waited to crucify us.

The Rat Stabbers are frisked in La Plata.

Rat Stabbers are herded in Banfield.

Boca Juniors cheerleaders in La Bombonera.

Racing's barra brava, the Imperial Guard.

Boca Culture in Buenos Aires.

Independiente fans at a may antiviolence rally in Buenos Aires.

His name was Jorge Celestre—Georgie Blueskies—but he was explaining the name of his fan club, the Rat Stabbers. They were the diehard supporters of Estudiantes, a pro soccer team southeast of Buenos Aires.

The first story was about some medical students—owing to their lab work, “rat stabbers”—who founded Estudiantes more than a century ago. It was a nice story about a studious, successful Argentina, a country that started the 20th century with futuristic dreams and progressive ambitions.

“But the second story is more probable,” Celestre explained as we jostled our way toward lines of police. The original fans were some unemployed men who sat around parks killing rats for fun. That squalid image evoked another Argentina, the one that ended the 20th century with riots and a currency crash, a backstabbing society where life is, as one Argentine put it to me, “a war of all against all.”

I had met the Rat Stabbers by physically pushing into their red-and-white-clad column as they marched toward the Cylinder, a high-fascist coliseum built in the 1940s by dictator Juan Perón—a Racing fan—with public funds. The swooping concrete is still dominated by Perón’s swan-necked tower, its omniscient eye now filled with the cameras of Copresede—a police surveillance agency called the Provincial Committee on Sports Safety—who are charged with stopping the most violent soccer fans in the world.

We squeezed through funnels of policemen watched by lines of horsemen and backstopped by rows of cop infantry in full riot gear. Specialists in nitrile gloves patted down the males in our cohort. ­Behind them were plainclothes Copresede agents holding mug shots of some of the 400 Rat Stabbers banned from their own team’s games.

The Rat Stabbers started up their brass band, for courage, and with a hard push about 2,000 of us were swept up the stairs and jammed into the visitors’ terrace. Here, penned by metal fences and more police, we were pressed shoulder-to-shoulder, immobile, for two hours, a single screaming entity heaving up and down.

Problem: we had 2,000, but the Cylinder seats 64,000. It wasn’t absolutely full, but I’ll stick with my guess that we were outnumbered by 60,000. They were dancing in great waves, a sea of blue and white, their noise drowning out even the Rat Stabbers’ band.

The game went badly. Not for Racing, whose diehard fan club, the Imperial Guard, gathered below our terrace, taunting, calling up challenges. Come down here and say that to my face.

The Rat Stabbers retaliated by spitting, and they managed to heave firecrackers and a smoke bomb over two layers of fencing. Nobody would remember the game later, not even the score. But they would remember this, the battle.

Goals are nice. But fighting is forever.

I’VE BEEN FASCINATED—OR should I say terrified—by Argentina’s violent brand of soccer since 1996, when I saw the Buenos Aires team Boca Juniors play in their notoriously tight little stadium, La Bombonera. Boca is famous for the quality of its play but also for its fan club—La Doce, the 12th Man—which has occupied the same north terrace for half a century, always standing, always singing, usually fighting.

That night, Boca fans began the match in style, igniting Roman candles that spewed red flames, sparks, and smoke over their heads. Enormous blue-and-gold flags unfurled from the upper levels. It was intimidating to watch from the opposite end, where I stood with a few thousand supporters of a team called Gimnasia, 50,000 people hating on me and my new friends.

The unaccountable happened: the unheralded Gimnasia handed Boca its worst defeat in half a century, a 6–0 stomper that sent waves of Boca fans crashing against the fencing that protected us. Trash and cups filled with urine rained down on us. Fleeing with Gimnasia fans, I found the streets of a great capital awash in cavalry and tear gas.

Don’t cry for Argentina. Brazil may be more famous as a soccer nation, the beautiful game embodied today by the 20-year-old juggler Neymar. And Europe remains soccer’s ­center of gravity: English clubs like Manchester United and Chelsea rule the global bandwidth, and Spanish clubs have ruled the pitch, bringing home two European champion­ships in the past five years.

Yet, often enough the Europeans get there with an Argentine: Barcelona’s striker is the shaggy-haired, fertile-footed Lionel Messi, the dominant player of this age. Sergio “Kun” Agüero and Carlos Tévez, who led Manchester City to this year’s league championship, are both Argentines. So is Paris Saint-­Germain’s Javier Pastore. In 2009, Argentina surpassed Brazil as the world’s top producer of soccer talent, farming out 1,700 players to professional leagues abroad. Soccer goes deep here—the first league was founded in 1891, the third-oldest in the world after England and the Netherlands.

But what Argentina really excels at is not so much the play of soccer as the bloodsucking financial exploitation and mob atmosphere that accompanies it. Corruption, of course, is nothing new in the sport. Italian teams are suffering their second ­major gambling scandal in six years, with reports of one player drugging his own team. Sepp Blatter, the four-time president of soccer’s global body, FIFA—the Fédération Internationale de Football Association—has set a low standard, trailed by clouds of bribery allegations and the same marketing scandal that recently brought down Brazil’s longtime soccer boss Ricardo Teixeira.

Of course, many nations produce dangerous fans. Games in Milan feature knife fights, England has long had its “firms” of hooligans, and racist “ultras” are a problem in Italy and Eastern Europe, where last year Polish fans threw Nazi salutes at Russian rivals. But the English hooligans of the 1980s fought for bragging rights, not money, and now they’ve been tempered by a national surveillance state. Across Europe, working-class fans have been outpriced by a move to champions or premier leagues, with their transnational schedules and sky boxes and crowd control.

Argentina’s fan clubs, meanwhile, have become “not quite as violent as the Bloods and the Crips, but similar,” says Andy Markovits, a University of Michigan political scientist specializing in soccer culture. In the 1980s, Markovits says, the fan experience in South America was “a cakewalk” compared with what was happening in Europe. Today it’s the reverse.

With nicknames like the Drunkards of the Stands, the Garbage Men, the Blue Pirates, the Gangsters, and the Scoundrels, the fan clubs for the 40 professional teams playing at Argentina’s A and B levels have been around almost as long as the teams themselves. But over the years, many of them have morphed into organized syndicates called barras bravas—literally “rowdy gangs”—that control most ­aspects of the teams. South American teams are private clubs, owned by their members. That leaves fan clubs, with their big voting blocs, able to make or break club officials and thereby control coaches and athletes. The most notorious barras—Boca’s La Doce, River Plate’s Drunkards of the Stands, and Quilmes’s Indians around Buenos ­Aires, along with Rosario Central’s Gangsters and the Lepers of Newell’s Old Boys in the ­provinces—have captured their stadiums’ concessions, monopolizing sales of soda, hamburgers, and jerseys. La Doce has one of the best scams, taking in somewhere around $125,000 to $150,000 a week in parking fees for home games. The barras routinely skim off players’ salaries. And, like Sopranos of South America, the strongest assert a criminal influence at the global level, taking cuts of the ­transfer fees charged when an Argentine player leaves for the European premier leagues.

But the barras don’t stop at profiteering: they have also been implicated in crime—from petty drug dealing, narcotics trafficking, and money laundering to beating not just rival fans but sometimes their teams’ own players. Last October, after San Lorenzo defender Jonathan Bottinelli scored an own goal to lose a game, three barra soldiers walked onto the practice field and beat him up—in front of his teammates.

Surely Bottinelli knew the history of recent killings. In 2005, for example, there were six soccer ­murders, including the shooting of a Rat Stabber during a massive fight with ­police. Five died in 2006, including a fan killed with a rock in a train station, and four in 2007, including two in internal fan-club feuds. Six were killed in 2008, another eight died in 2009, and 2010 saw 11 deaths, including a Boca fan beaten by rivals at the World Cup in South Africa and the wine-bar assassination of the country’s most powerful barra leader.

When I landed in Argentina in May, the violence was mounting faster than ever. A Nueva Chicago supporter was beaten to death with a crowbar in an internal feud; a few days later, a rival was killed as payback. A faction leader from the Drunkards was shot in the head. Three Rosario fans were gunned down by someone from Newell’s, and during my visit, some Unión fans shooting at a Newell’s crowd accidentally killed a bystander. By the close of the season in June, the death toll was already nine. And a new season would begin in August.

That violence has degraded the game itself. Every player who can follows Lionel Messi abroad, and when these dispersed stars do ­reas­semble as a national team, they crumble rather than cohere. At the 2010 World Cup, Argentina covered the South African grass with talent but was humiliated: Messi was unable to score a single goal in the tournament, and the Germans packed their bags 4–0.

This sense of rising crisis, of a country and a sport destroying itself, was what lured me back to Argentina. The Argentines invented a new way to steal money, they used it to crush their enemies, and now they will ruin their own beautiful game. All while raining goals.

SUNSHINE KILLS MAFIAS, BUT the sun goes down early in the ­autumn streets of Buenos Aires, and the evening game is still hours away as photographer Marco Di Lauro and I turn up a small street and come face-to-face with about 500 members of La Doce, Boca’s notorious fan club. The hardcore of La Doce always rally before a game in a parking area three blocks from the stadium. Tetra Pak boxes of cheap wine are piled in pyramids, clouds of marijuana drift everywhere, and the testosterone flows freely. Everyone is dressed in blue and gold, including me. I’ve borrowed a natty blue zippered number, emblazoned in gold with an elaborate club seal: CABJ, for Club Atlético Boca Juniors.

Boca. Not just the most famous team of any sport in South America but an icon, a myth. The Boca neighborhood is a grimy working-class port, and the team represents the poor man’s side in the class war that is Latin America. Boca has underdog charisma but wins like the ­Yankees: scores of national titles, as well as five South American championships in the past decade alone. It has its own museum, where you can buy thong underwear in team colors. Outside you can get your picture taken with a statue of Diego Maradona, the avenger who rose from the slums to dominate the global game and humiliate England with his infamous Hand of God goal at the 1986 World Cup. Twenty-five years later, the sight of Boca’s blue-and-gold strikers coming up the field is enough to tighten the sphincter of any goalie.

Our guide is Sergio Caccialupi, known to everyone as Paco, a grizzled Boca fan and a member of La Doce since the 1970s. Paco has agreed to escort us for an extortionate ticketing fee ($150 apiece), typical at Boca games. He is thin-faced, jittery, and scarred—­according to his autobiography, sold at the stadium store, he spent the 1980s peddling 30 kilos of cocaine a week, survived two jail terms, and once went all the way to Rio to fight supporters of another team. (“Better a thief than a policeman,” his father told him.)

Despite my suit of blue armor, I’m immediately threatened with stabbing, robbery, and buggering. But that’s par for the course, a sign I’m being accepted, or at least tolerated. Taunting is the core of hooligan life, and I plaster a broad smile on my face and take a nip of whatever is handed to me—red wine mixed with Coca-Cola, then red wine with orange soda, then Fernet with lime soda.

Trying to establish my bona fides, I mention that I was present here when Boca suffered its worst defeat in half a cent—

“Six to zero,” Paco says.

“1996,” another voice says.

“Gimnasia,” a third man adds. “That was the worst day of my childhood.”

I’m losing friends quickly. The men talk among themselves in lunfardo, the rapid Italo-Spanish dialect of Buenos Aires. “They have to pay,” one man says. Another warns Paco, “Don’t let them see anything.” Another volunteers to his friends that he’ll rob me if he gets the chance.

I call him out. “Why are you going to rob me?”

“That’s what I do for a living,” he replies coolly. On weekends he goes to Boca games. Monday to Friday, he robs tourists in the same neighborhood. If I go walking around, he says, “90 percent chance we will rob you.”

Time for protection. We give Paco the agreed-upon fee for two ­entries to the La Doce terrace. Cash, no receipts. Paco assures me that numero uno himself—La Doce boss Mauro Martín—has approved our attendance, and indeed, a few minutes later Martín strolls past in a white track suit, his red eyes giving us a once-over.

We’re in.

NINETY MINUTES BEFORE THE game, Paco suddenly says, “Let’s go.” We follow him not toward La Bombonera, its steep concrete walls painted blue and gold, but down a side street, through a quiet tennis stadium, and into some locker rooms before emerging to face a high fence of sheet steel. A knock, and a door opens. We are suddenly at the stadium gates, having skipped three lines of security. It’s amusing to see a dozen Buenos Aires officers look away deliberately. We go straight to the entrance of the tribuna popular, the world of La Doce. It’s the celebrity treatment, the Paco passage.

We do have to go through the turnstiles themselves. “Where are you from?” a policeman asks as he pats me down. America, I tell him.

“Welcome,” he says. And, looking up from my ankles with a smile, “Good luck in there.”

Paco hands us our “tickets,” digital passes that belong to someone else—in my case, a youth named Mariano. Marco, an Italian war photog­rapher who has spent more than 1,300 nights embedded with troops in Afghanistan, is apparently my mother, Maria.

We climb slowly up four flights of stairs—Paco, worn by hard ­living, has to rest on each landing—to reach the terrace, perhaps the most feared and tightly defended real estate in world soccer. “You have to sit here,” Paco says, indicating a section on the left. “You can’t take pictures over there,” he says, turning toward the center. “Stay away from that part. It’s where the boss sits. Don’t even point your camera over there. You can take pictures in other directions, but don’t even look over there.”

The regular Boca fans pile in during the next hour. La Doce has no official membership—“Only the police keep a list,” Paco says—and our terrace packs in with four or five thousand fans. But just a few minutes before game time, the dedicated core of the barra brava march in. These are our 500 friends from the parking lot, singing and waving huge flags as they follow the band to that central forbidden zone. ­Mauro Martín is in there somewhere, hiding from photo­g­­raphers behind a ring of loyalists and a drapery of banners. (“If they become famous, they get arrested,” a police officer told me.)

Martín is not the only boss in the house. Diego Maradona has flown in from Dubai, where he coaches a team called Al Wasl. Various ­derailments—cocaine, tax evasion, a brief exile in Cuba—have only deepened the love affair between La Doce and their idol, who sits in a box at midfield.

The singing builds, the flags wave, and for a while we are inside the joyous machine of a fan club, exactly where I always dreaded, a stomping, jeering, cheering, and drunken band of warriors. The ­enemy—the Brazilian team Fluminense—takes the field amid a deafening chorus of 40,000 boos. When Boca comes out, La Bombonera explodes into a wall of bass drums and chanting: Dale, dale, Bo! Dale, dale, Bo! Dale, dale, Bo! Bo-ca! Let’s go, Boca!

The Brazilians give the stadium a scare: two quick attacks on goal. La Doce only sings louder, draining the atmosphere with a version of “Volare” for 20,000 voices. Yet few of us can even see the action. There are too many banners draped over our heads, and many fans sit facing not the field but the band. Petty drug sales are one of La Doce’s biggest rackets, and dark green buds are passed around openly, rolled up, and smoked in titanic quantities. Putting a buzz on top of a drunk leaves quite a few fans in the same state as Paco—so wasted, so early, that he lists to one side, nodding to the simple beat of the chants.

A string of menacing tough guys approaches, threatening us if we take pictures. One says, “This is our house. Nobody takes pictures in our house. Nobody.” Paco has promised us this access, but he’s too drunk to speak, and my Boca jacket has no magic here. A wiry, wide-eyed man screams at us bluntly: “You take one more picture, your cameras are going to fly through the fucking air!”

Game over. The Brazilians suffer a sudden setback, a red card to their player Carlinhos in the 34th minute. Two riot policemen escort him off the field under a hail of small objects tossed down by La Doce. The match turns into a mismatch: 11 Boca players grinding down 10 Fluminense rivals. The Boca striker Pablo Mouche eventually slides one across the mouth of the Brazilian goal.

Fluminense almost get an equalizer, but a Boca player blocks the shot with his right arm. It’s one of the few plays I witness, occurring right below us. But the referee doesn’t see it, and the fans don’t want to. Diego “Hand of God” Maradona is in the house. Boca wins 1–0.

THE FIRST MURDER SPAWNED by Argentinean soccer can be traced to 1924, when a Boca fan shot a Uruguayan rival during a tango-style showdown outside a luxury hotel in Montevideo. Sometime in the 1950s, the fan clubs organized for self-defense. La Doce took its fierce, fistfighting form in the 1970s. Then, around 1981, in the last violent days of Argentina’s military dictatorship, the fan killings ­accelerated. Journalist Amílcar Romero, who wrote a history of soccer—this country also produces philosophers and artists specializing in the sport—divided the violence into three ­periods. Only 12 fans had been killed during the roughly 30 years following that first hotel murder. In the next three decades there were 102. The next 30 years saw 144 dead.

But Romero counted only game-day deaths. The antiviolence group Salvemos al Fútbol tallies 269 soccer-related deaths in its running count—with much of the killing moving off-site in recent years. In 2009, for example, the former Lepers leader Roberto “Pimpi” Camino was shot four times while leaving a wine bar late at night. Today the violence often takes place within the fan clubs themselves, in fights to control the barras’ growing incomes and the benefits of their power. “They fight over money and women,” one sportswriter told me. (He insisted on anonymity, saying, “No Argentine journalist could write this story,” for fear of retaliation.)

One of the few to take that risk is a five-foot-three-inch platinum blond lawyer from Buenos Aires. Forty-four-year-old Fabiana Rubeo is a Boca devotee, but she grew tired of seeing soccer ruined by its fans. In 2006, she founded an antiviolence non-profit called New Horizon for the World. Tiny and unthreatening, she charmed 160 leaders from more than 40 barras into attending a peace summit, where they agreed upon a Ten Commandments of barra etiquette.

Yet, the first thing Rubeo tells me when I show up at her office is that she has given up her campaign. She was threatened by criminals, ignored by the government, and mocked as “naive” by the Buenos Aires newspaper Pagina 12.

“Nobody supported us,” she says. “I don’t want to be Don Quixote tilting at windmills.” All that’s left of her effort is an agreement by gang leaders to throw back balls that land in the stands.

“Here, everything is mixed up between soccer and politics,” Rubeo says. She cites the example of Bebote (“Big Baby”), the current Red Devils leader from Independiente, whose real name is Pablo Alejandro Álvarez. Thanks to a close relationship with a trade-union leader and other politicians, Rubeo says, Big Baby got a lucrative travel concession, flying barra leaders to the 2010 World Cup at government expense. (South African authorities deported most of them immediately.) Likewise, Rafael Di Zeo, the former leader of La Doce, worked for the local legislature for years, before his love of publicity and stadium fighting combined to put him in jail.

Why doesn’t anyone fight back? Politicians keep the barras on speed dial, using them as paid flash mobs in the country’s fuerza de choque. This is the “collision of forces,” an Argentinean style of politics in which rightists, leftists, unionists, and any group that wants anything must put protestors in the streets. The fuerza de choque is a war of perpetual demonstrations and pickets, road disruptions and blockaded buildings. Soccer-style thuggery has infected the highest levels of politics; the president’s own son leads a nationalist “youth group” that stormed Congress in May, waving flags and shouting fight songs. Two years ago, an administration official who disliked a new book about inflation called on the fan club of Nueva Chicago. About 15 barra soldiers then raided the Buenos Aires Inter­national Book Fair, threw chairs, and fought secu­rity guards while chanting slogans against the startled author.

Rubeo puts me in touch with someone who knows one of these dangerous men—the head of the fan club for Lanús, a team from greater Buenos ­Aires. She wishes me luck but issues a warning. “Fútbol,” she says, “is like a Mafia family. If you are not in the family, you don’t come inside.”

The gangster meets me in a tobacco-stained bar on a cool autumn afternoon. He is huge, mostly muscle but wrapped in a layer of fat and covered in ­tattoos from his neck to his wrists.

He says that I should “gratify” him, a refer­ence to money, not sex. A Spanish TV crew paid him $5,000, he notes. I demur.

“I’ve been the leader of this barra for 12 years,” he says, suddenly angry. “I’m the long­est-serving leader in any barra. You under­stand what that means? We’re wanted men. We don’t do this for free.

“Argentina’s the best in the world at this,” he boasts. If only he means soccer.

Four days later, before a Lanús home game against All Boys, three barras on motorcycles open fire on Lanús fans, killing 21-year-old Daniel Sosa and wounding five others. Police recover three guns from outside the stadium.

The game starts a few minutes later.

MURDER HAS A WAY of improving things. Until 2010, the Rat Stabbers were among the worst in a nation of bad fan clubs and had driven ordinary fans away from Estudiantes games. But late that year the Rat Stabbers went too far, killing a policeman during a brawl.

Copresede dismantled the club. Leaders were jailed, and 400 dangerous fans were banned from the games. Since then a more normal fan club has emerged. Three weeks ­after my first outing with the Rat Stabbers, Marco and I join them in their hometown, La Plata, a chilly city on the coast southeast of ­Buenos Aires. We find the fans milling around a red bus on a Saturday morning, wearing the red-and-white jerseys of their team.

Georgie Blueskies is here, leading a subgroup of the new Rat Stabbers. Stout and deep-voiced, he embodies the reformed, middle-aged new fan—his ponytail ­going silver, his demeanor reflective. Women and even children are back at the games, a glimpse of what fútbol could be in this most productive of fútbol nations.

“These are normal people,” Celestre emphasizes as he drives us across town in his (red) muscle car, following the (red) bus to pick up more (red-clad) fans. “We’ll see how long that lasts.” Without constant police pressure, he says, the old violence will return, because the opportunities for corruption are always present in soccer.

“Here at the local level, it’s normally just ticket sales, parking, a portion of travel costs,” he says. “In other clubs there’s more money: the sale of shirts, even a percentage of a player’s salary. The leaders are always ­allied with politicians, with whichever party is in power.” The barras are becoming “executive gangs,” he says; some leaders are lawyers and professionals who mix with politicians in the expensive seats.

Celestre isn’t impressed with Copresede, whose list of 400 banned fans turned out to include a lot of dead people and children. “They are useless,” he says. “They never protect us from anybody.” He complains that some Rat Stabbers were recently attacked with stones and bottles by my old friends from Gimnasia, their rivals across town.

We end up at a traffic circle outside La ­Plata, massing for the drive to a game with archrivals Banfield, southwest of Buenos Aires. Their last game was canceled after Rat Stabbers threw firecrackers at the Banfield goalkeeper.

There are thousands of other fans, in 13 buses and a fleet of private cars. We’re surrounded by 100 or so cops, including a ­police bus, a dozen squad cars, and motorcycle ­officers riding tiger-striped bikes and wearing shotguns slung across their backs. The cops frisk anyone suspicious, meaning all the dark-skinned or rough-looking young men.

I briefly meet the Rat Stabbers’ leader, the extremely tall Ruben Moreno, who is very mellow, befitting the ­Spicoli-grade stoning he appears to have going. (“Welcome, welcome, no problems here.”) He is one of the Rat Stabbers banned from the games, so he won’t be traveling with us. But he has to stand around in the mud handing out the fundamental currency of his patronage network: free tickets.

The cops toss the buses, throwing (empty) wine cartons out the windows, and after some negotiation—we’re warned off one bus set aside for extra-heavy pot smokers—we board the musicians’ bus, a relatively calm one with some grannies on it.

Our convoy moves at a crawl, stretching the 75-mile drive into a three-hour parade. We roll like contractors in Fallujah, preceded by a flying squad of motorcycle policemen, the 13 buses interspaced with squad cars, more motorbike cops patrolling the flanks. As soon as we are moving, the beer comes out (it was hidden by the driver, under his legs) and then the weed (it was stashed inside a drum). The clouds of dope are kept to the back of the bus, somewhat, but I think the grannies are affected, because the whole way they are singing at the top of their lungs: We’re the Rat Stabbers / We smoke marijuana / And run from the police! Or this one, specially composed, perhaps: Everyone from Banfield is a whore! / Everyone from Banfield is a whore!

Finally, we shudder to a halt near the pitch. “Women first!” every­one shouts, which leaves a thousand men free to urinate on every fence in the neighborhood. Hundreds of grilled chorizos are bought and wolfed down in seconds, and we jog toward the stadium like a red tsunami. Inside, the younger fans unfurl their flags and the Rat Stabbers begin to sing and jump in place, overwhelmed by the joyful, forging power of being outnumbered during a raid on hostile territory. Even better, Estudiantes scores early, and then scores again, creating an ecstasy not seen since the Oracle at Delphi.

The Banfield fan club—called the Band of the South—isn’t amused, but the reactions of a mob are notoriously hard to predict. Every Argen­tinean game is rated in advance as low, medium, or high risk for violence; today is high risk. But the police have learned a lot over the past decade of murder and mayhem, and enormous riot fences separate us from Banfield’s seething barra brava.

It turns out that the cops welcome journalists for the same reason the barras don’t: publicity hurts criminals. I climb a surveillance ­tower looming six stories over the stadium and join a Copresede security team in a small control room. The officers are using cameras to zoom in on a young Rat Stabber trying to tear down the fencing. Walkie-talkies let them coordinate with a uniformed cop reporting a fight in the Banfield section. As the fighting builds, a pudgy, curly-haired officer in a dark blue sweater, Guillermo Suarez, cries out, “We’re going to have a quilombo,” slang for a huge mess. “Get an infantry cordon over there!” But some fans intervene, and medics soon pull the victim away.

Bored, Suarez shows me how to aim a camera at any part of the stadium, even the hallways. The passivity of watching everything all the time brings out the psychoanalyst lurking in every Argentine. “There’s no line between barra and not-barra,” he observes. “Look at those stands over there. Those are good seats. You’d think they were rational people. Professors. Good people. But it’s incredible. They go crazy.”

From up here, I watch the Band of the South, which has unfurled banners demanding the release of their jailed leaders. Banfield is ­going down—the final score is 3–0 Estudiantes—but the Banda is up, roaring, cacophonous, undoing some of the misery of their defeat.

After the game, the hardcore barras from Banfield wait outside their stadium. A hundred men in green track suits are chanting their loyalty in the cold, muddy street. It’s a frankly fascist scene: the agitated young fans displaying power, their heads shaved or cut close, their chants, their groupthink, their insistence on the superiority of their own side. Juan Perón loved soccer crowds.

While Marco and I are gawking, police cordons push the Rat Stabbers back onto their buses, and they drive back to La Plata. Stuck on foot in nowheresville, we dodge the angry Banfield mob and grab a public bus heading back to Buenos Aires. But the Rat Stabbers’ day isn’t over. During a roadside stop, some local men throw rocks at their caravan; everyone defends themselves, the younger Rat Stabbers pouring off the buses to retaliate. Police fire tear gas and rubber bullets, and the bus with the grannies has its windows smashed by rocks.

This smackdown doesn’t make the news. Not even the ­soccer news, where a “temperature report” in the national newspaper Clarín ­records the week’s fútbol outrages. (Fans of a team called Italia threw syringes at their own coach; the president of Independiente got ­another death threat; after a loss, 44 members of a Cordoba fan club ambushed their own players’ bus, threatening “a bullet for everyone” if the team didn’t advance a division.)

A riot. Some rocks. Gas guns. It’s just background noise.

IN THE END I find a clásico, a match between historic rivals. This turns out to be Boca at Racing, the same stadium where it began for me three weeks earlier with the Rat Stabbers. Now it was La Doce’s turn to force their way into the Cylinder.

La Bombonera is only a few miles away, so La Doce always marches there, across the dirty Río Riachuela on the Old Bridge. It’s more an invasion than a parade, and Marco and I narrowly avert a beating from a fan leader who recognizes us from the previous game. He draws a finger across his neck and tells me, “If you take a picture, we’re going to throw you in the fucking river.”

His threat is backed by a surging crowd of several hundred hardmen pushing toward us across the bridge. Chanting and waving flags, La Doce pours toward the Cylinder, with Marco and I running just ahead of them. We find refuge in a taxi, duck down, and are scooped up at the stadium entrance by friendly Guillermo Suarez from Copresede. “You just saved our lives,” Marco says.

Racing’s Imperial Guard puts on a huge display of sound and fury; there is confetti, a blazing red marine flare, and firecrackers thrown across the moat at the Boca goalie (they miss). The Guard have a nearly 60,000-man advantage over La Doce, but the Boca fans unfurl some old Racing banners they stole during previous street fights, a dangerous taunt. Copresede phones a Boca leader, and the war prizes disappear within minutes.

Finally, here is a real game, worthy of the title clásico. Our pals in the police let us onto the field itself, where we sit at the midfield line, smelling sweat and the acrid tang of smoke bombs. We’re so close that Boca’s hawk-faced coach, Julio César Falcioni, nearly runs me over while disputing a call.

For a moment, I can live in the beautiful game. Some of the world’s top athletes are tearing up the grass, and the play is fast, passion­ate, and clean—men shaking hands after knockdowns, a display of sportsmanship so missing in the stands. Protected by perhaps 1,000 cops, I finally feel safe in an Argentinean stadium.

A bit later, up inside the swan-necked tower, I join Suarez and five of his colleagues in the cramped Copresede surveillance center. Fifteen screens show feeds from 14 fixed cameras and 13 mobile units. The very top of the tower holds a swiveling camera with a super­powerful telephoto lens that Suarez controls with a joystick. We watch a man lighting a joint, then another pissing in a corner and a third getting beaten up by members of his own fan club. (“Copy,” Suarez says to an ­officer out in the terraces. “It’s to the right of the Rolling Stones banner.”)

Someone is shining a green laser in the eyes of the referee. Abusing the ref is normal—at Maracanã stadium in Rio, I saw fans shoot flare guns at one official—but Suarez and two colleagues rewind the footage and quickly track the laser to one corner of the Imperial Guard terrace. Suarez swivels his joystick and the camera locks onto an acned, monobrowed individual in a striped Racing jersey, holding his left hand to his ear. “Got him,” Suarez says. A beefy technical assistant hits the print button, and four copies of the kid’s photo are dispatched to police at the four exits used by the Imperial Guard.

The game is playing on a small television in the corner, ignored. I go back down to the smoke-filled arena, to my privileged spot beside the grassy action. In the first half Racing presses hard, dominating the ball, running triangles and through passes, to the delight of the Imperial Guard. But in the second half, the Boca striker Lucas Viatri receives a lofted pass to the middle. Facing away from the goal, he splits his momentum—a back-footed tap to the right, a quick turn to the left.

It takes only a second to relieve an hour of tension. Stepping around a flat-footed defender, Viatri reunites with the ball on the first hop, drilling a roundhouse. Time stops, physics takes over. The back of the net billows out. It is improbable, beautiful. Not just a gol but a golazo, according to the next day’s Clarín.

In Argentina, tomorrow is always better than today.