An act of the US Congress that curbed the power of trade unions. It banned the closed‐shop and the secondary boycott, allowed employers to sue unions for breach of contract and for damages inflicted on them by strikes, empowered the President to order a 60‐day “cooling‐off period” before strike action, and required union leaders to take oaths stating that they were not communists. Despite protests from the unions, it has remained relatively unchanged.