Autoworkers at a General Motors plant in central Mexico delivered a landslide victory to an independent union in a vote held February 1–2. It’s a major breakthrough for workers and labor activists seeking to break the vice grip of the employer-friendly unions that have long dominated Mexico’s labor movement.

Turnout among the plant’s 6,300 eligible voters was 88 percent. The independent union SINTTIA (the National Autoworkers Union) picked up 4,192 votes — 78 percent of the vote. SINTTIA, which grew out of the successful campaign that ousted the previous, corrupt union last year, promised to raise wages and fight for workers on the shop floor.

Workers at the plant in Silao, Guanajuato, voted last August to invalidate the contract held by a well-connected national autoworkers union headed by Congressman Tereso Medina of the Institutional Revolutionary Party (PRI). That union was affiliated with the Congress of Mexican Labor (CTM), the country’s largest union federation.