Starbucks has fought these efforts tooth and nail along the way. The National Labor Relations Board, which regulates private sector union activity in the U.S., has found the company illegally fired workers in response to organizing, closed stores because of union votes and engaged in widespread unfair labor practices designed to quash workers’ efforts.

The coffee conglomerate is the biggest violator of labor law in modern history, according to Starbucks Workers United, the national union representing company workers. The NLRB and its judges have found Starbucks has committed more than 500 labor law violations, the union says. Workers have filed more than 1,000 unfair labor practice charges, including more than 125 since January. More than 700 unresolved charges remain.

Despite the hundreds of union votes over the past four years, baristas are still working without a contract. This month, 92% of union workers voted to authorize an open-ended unfair labor practices strike ahead of the holiday season. The vote comes after six months of Starbucks “refusing to offer new proposals to address workers’ demands for better staffing, higher pay and a resolution of hundreds of unfair labor practice charges,” the union said in a news release.