When the Mexican government moved to bust the three-year miners’ strike in Cananea on June 6, it brought 2,000 Federal Police into the tiny mountain town in the state of Sonora—two cops for every striker. As darkness fell and helicopters clattered overhead, they charged the gate with riot shields and batons, filling the streets with tear gas. Miners retreated to the union hall with their families, and the police followed, barricading the doors and lobbing more tear gas inside.

The union’s leaders were already in hiding, since the police had arrest warrants for them all. Manny Armenta, an organizer for the United Steel Workers who’s probably spent more time in Cananea than at home in Arizona, helped lead women and children down fire escapes and through the basement to safety.

The same day, police moved on the widows of sixty-five miners who had died in an explosion four years ago at the Pasta de Conchos coal mine in Coahuila. Women were forcibly removed from the mine gates where they’d been camping, asking for their husbands’ bodies. Grupo Mexico, the mining and railroad giant that owns both facilities, is closing the mine for good without recovering the men’s remains.

Both the Cananea strike and the widows’ protests highlight extremely unsafe conditions in Mexican mines. At Cananea, silicosis-causing dust from crushed copper ore rises to miners’ knees inside the buildings. Grupo Mexico disconnected the dust extractors several years ago, in retaliation for earlier protests. At Pasta de Conchos, dozens of uncorrected violations for dangerous methane buildup preceded the 2006 explosion.

But the Cananea strike goes beyond health and safety issues. For three years the Mexican Union of Mine, Metal and Allied Workers, commonly known as the Mineros, has challenged the National Action Party (PAN), which has governed Mexico since 2000, and its corporate backers, especially Grupo Mexico and its owners, the Larrea family. In turn, Mexican President Felipe Calderón has systematically sought to destroy the Mineros, as well as other unions that defy him. Last fall he fired 44,000 members of the left-wing Mexican Electrical Workers Union (SME) and dissolved their state-owned employer, the Power and Light Company of Central Mexico. Progressive unions believe that destroying the SME would remove another union challenge while preparing the way for privatizing electrical power generation. SME members fasted in protest and were beaten this spring at the gates to the power plants.

In the face of these attacks, the Obama administration has been silent. Armenta believes the attack on Cananea’s miners is the consequence not just of Calderón’s antilabor policies but also of tacit US support for them. "Our government continues to give the Mexican government millions and millions of dollars, saying it will be used to fight drugs," says Armenta. "But we see here clearly that this money is going to fight workers and progressive people."

On May 19 Calderón was feted at a state dinner at the White House. Leaders of the Steel Workers union met with administration officials, asking them to tell Calderón they wouldn’t tolerate an attack on the miners. AFL-CIO president Richard Trumka and Canadian Labour Congress president Ken Georgetti wrote to Washington and Ottawa with the same demand. According to Armenta, officials "assured us they were not turning their heads away. That was totally false." Eighteen days after the banquet, police attacked the Cananea miners.

The Mineros used to be a loyal ally of the old Institutional Revolutionary Party (PRI), which governed Mexico for seventy years. But Napoleón Gómez Urrutia, who took over the union in 2001 from his father, a PRI stalwart, had much more militant and democratic ideas. He quickly forced employers, including Grupo Mexico, to concede much higher wage increases than those mandated by then-President Vicente Fox. Gómez helped defeat Fox’s reform of Mexico’s labor laws, a proposal recommended by the World Bank that would have eliminated the right to strike and other protections and social benefits for workers. After the Pasta de Conchos explosion, he accused Grupo Mexico of "industrial homicide."

The government reacted violently. It accused Gómez of corruption, forcing him to flee to Canada to avoid arrest, where he has lived ever since. A government-backed effort to install a pro-company union leader was twice rejected by the workers, who re-elected Gómez in exile. All the legal actions against him led to his exoneration, but the government still threatens to jail him if he returns to Mexico.

In June 2007 the Mineros struck the Cananea mine over safety conditions. The following January, after police beat dozens of workers in an attempt to break the strike, 25,000 Mineros members struck in protest at ten mines and at the huge steel mill in the port city of Lázaro Cárdenas. Two workers were shot and killed there, where the turmoil continues. This year twenty more were beaten when they shut the mill down again and marched in the streets.

Government-dominated courts and labor boards have repeatedly declared the strike at Cananea legally "nonexistent," a decision allowing Grupo Mexico to fire the strikers and install a company union. After Calderón won election in 2006, with major contributions from the Larrea family, the labor board gave legal status to a new, company union, or charro. A rump election and the firing of 1,500 workers at a neighboring copper mine in Nacozari led to recognition there of the company union, followed by similar moves at several other mines.

According to the Mineros, Labor Secretary Javier Lozano recently held meetings with mine owners, offering government recognition of the charro union in order to get out of contracts with the Mineros. Calderón himself was recently the guest of honor at a Mexico City bash hosted by the Chamber of Mines. "The government and the Larreas are making history, but backwards," the union responded after the occupation of Cananea, "trying to return to an era when we had no right to strike or right to industrial safety."

Smashing the Cananea strike will lead to the same massive firings that followed an earlier lost strike in 1998, and the destruction of the union in Nacozari in 2006. When that happened, waves of desperate miners, unable to find other employment, crossed the border into the United States as undocumented workers.

"Especially here in Arizona with the new law, all we hear about is illegal immigrants," Armenta says. "But our own government is creating this problem. I condemn the Mexican government, and Grupo Mexico. But I also condemn the US government for allowing this to happen, for not taking any action. What do they think will happen here? Where do they think all the miners will have to go?"