Despite the modest protections of the NLRA and the active threat of the Mackay doctrine, workers in the mid-1940s launched another massive strike wave, which included over five million workers at public utilities and in industries like coal and steel, meatpacking, and auto manufacturing. In 1946 in Pittsburgh alone, 120,000 workers went on strike. This time, instead of passing legislation that would calm strife as it had in 1935, Congress did the opposite. In 1947, it ratified the Taft-Hartley Act, or the Labor-Management Relations Act, even over the veto of President Harry S. Truman. This vile law establishes a litany of constraints on union activity. It prohibits certain strikes and boycotts. It limits union political power by banning federal campaign contributions. It allows states to pass right-to-work laws, which were first championed by Jim Crow architects as a way to prevent the coming together of Black and white workers into the same unions.