Mexican GM Workers to Vote Next Week on Union at Second Plant

Workers at a second General Motors assembly plant in Mexico will vote June 25 to 27 on whether to join SINTTIA (the National Auto Workers Union), the independent union that won a landmark election to represent workers at the company’s Silao plant in 2022.

A win for SINTTIA at the plant, located 90 miles north of Silao in San Luis Potosí, would mark a major breakthrough for Mexico’s labor movement. It would be the first time that an independent union represents two assembly plants at one of the Big Three automakers.

The 6,500 workers set to vote produce the GMC Terrain and the Chevrolet Trax and Equinox SUVs.

PROTECTION UNIONS

GM workers in San Luis Potosí voted out their previous union, a Confederation of Mexican Workers (CTM) affiliate, in 2023. The CTM has built a reputation for imposing pro-boss “protection contracts” that lock in low wages and prevent true union representation.

After the company union was voted out, GM created a “labor council” at the facility to address labor relations at the plant. But the company alone appointed workers to the council, and it filled the council with loyalists from the old union.

The day SINTTIA’s campaign at the San Luis Potosí plant went public, the labor council disbanded and the majority of representatives on the council began collecting signatures for a rival union, Carlos Leone, with ties to CTM.

SINTTIA supporters allege the rival union is being helped by GM to stop workers from forming a genuine union. Carlos Leone supporters from the disbanded labor council have been allowed to collect signatures for Carlos Leone on company time. They were also working off a full list of employee names, dates of hire, and CURP numbers (similar to a social security number)—all of which are needed to file for union representation—which could have only come from GM. SINTTIA has not been given access to the same lists, nor have their organizers been permitted to collect signatures on company time.

The Carlos Leone union also cropped up recently in Silao, where workers at a Pirelli tire plant have been seeking to join an independent union and to bring the plant under the sector-wide agreement covering the rubber industry.

Some allege that the Carlos Leone union, which was originally registered to represent workers in hotels and restaurants south of Cancun, is a front for the CTM and has ties to organized crime. “It’s a paper union,” said a longtime Mexican labor activist. “It’s for sale to the highest bidder.”

SÍ, SÍ, SINTTIA

SINTTIA has represented the 6,500 workers at GM’s plant in Silao, Guanajuato, two hours south of San Luis Potosí, since 2022, after workers ousted an employer-friendly union affiliated with the CTM (and headed by former senator Tereso Medina, one of the most powerful men in Mexico). It was a hard battle: after the CTM destroyed ballots in a vote the previous year, the U.S. Trade Representative pressed Mexico to ensure fair elections at the plant.

Since then, SINTTIA has won double-digit raises annually, including a 10.25 percent increase earlier this year.

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But GM management in San Luis Potosí has matched everything SINTTIA has won in Silao, which supporters of the independent union say is intended to dissuade workers from joining SINTTIA.

Despite recent gains, Mexican GM workers still earn between $3 and $7 an hour. A win in San Luis Potosí would mean SINTTIA represents 13,000 Mexican GM workers, offering significant leverage in its fight to bring up wages in Mexico’s low-paid auto sector.

SOLIDARITY MESSAGES

SINTTIA is asking for statements of solidarity from workers and their unions. The union asks for short statements, videos, or photos expressing support for the workers of GM San Luis Potosí in their fight for authentic union representation.

Send solidarity messages to calis.nacional[at]gmail[dot]com and cilas[at]prodigy.net[dot]mx.
Their call is below:

Call for solidarity with SINTTIA and the struggle of the General Motors Workers of San Luis Potosí

San Luis Potosí, June 12, 2025

To independent and democratic trade union organizations. To the world's unions in solidarity with the struggles of workers in Mexico. From June 25 to 27, the more than 6,500 workers at the General Motors plant in San Luis Potosí (GM SLP) will vote on which union will represent them. After a patient organizing process, SINTTIA is close to a win at a second GM assembly plant. However, with the company's support, a pro-employer union entered the dispute for union representation.

For SINTTIA, this election is of great importance because it would mean its expansion to a second automotive assembly plant in one of the "Big 3" in the sector, which would give SINTTIA a key strategic strength for defending the interests of automotive workers in Mexico, especially amid Mexico's complex trade and economic context with the United States.

From SINTTIA we ask all independent and democratic unions, both in Mexico and around the world, as well as social organizations, workers in the sector and in general all those who defend and sympathize with the struggles of workers and the advances of independent and democratic unions to express their solidarity with the workers of GM SLP by any means at their disposal (statements, short videos or photos of solidarity, etc.) so that GM SLP workers know that they are not alone and break their fear.

Key ideas for statements of solidarity:

• June 25, 26 and 27: Vote without fear, vote for SINTTIA
• An independent union is the best option
• Calls on the company to keep its hands off the process
• Call on authorities to guarantee the exercise of free, personal, direct and secret voting
• Denunciation of protection unionism
• The importance of losing fear and voting for change

For more background on the vote, see “Will Mexican GM Workers Get a Fair Union Election?”