One of Santa Clara County’s virtues for firms looking to relocate or expand there was the lack of a strong industrial union presence—not an uncommon rationale for selecting a rural factory site. Like railroad engineers, salaried engineers at firms such as HP and IBM remained tough to organize, but some hourly production workers armed themselves with the National Labor Relations Act and bargained collectively. At military contractor Westinghouse’s Sunnyvale plant, the left-wing United Electrical Workers won an election to represent hundreds of workers, beating out more conservative unions. The UE entered the postwar period as the third-largest member union in the CIO with 700,000 workers, including around 300,000 women.35 But the UE had a strong communist current, and in 1947 when the Republican congress passed the Taft-Hartley Act, which required union leaders working with the National Labor Relations Board to affirm that they were not communists, the UE refused to comply. Soon they split entirely with the CIO, preparing it to merge with the tamer and less radical AFL. Marginalized by the increasingly anticommunist mainstream labor movement and shackled by Taft-Hartley, with its ban on sympathy strikes, the UE withered. In 1956 it lost its Westinghouse reelection, and by the end of the ’50s it was redbaited out of burgeoning Silicon Valley. This hit women on the production lines particularly hard. Historian Glenna Matthews writes that “[w]hen the UE lost its vital presence in the Valley, women workers lost their best chance of having labor commit resources to organize them.”36 Uncoincidentally, Silicon Valley firms used immigrant women to fill nonunion low-wage assembly jobs in the coming decades. Warned by example and freed from internal competition by Taft-Hartley, Santa Clara County union leaders stayed friendly with management.37