The union represents only a fraction of Starbucks stores in the U.S., but the labor movement has been described as the company’s biggest yet — and it could have a significant impact on Starbucks as the holiday season approaches.

Unionized Starbucks baristas say they're ready to strike on Nov. 13 unless the company finalizes a labor contract.

Michelle Eisen, a spokesperson for the union who left Starbucks after a 15 year career at the company, said in a statement: "If Starbucks keeps stonewalling, they should expect to see their business g...