Final answer:
The Taft-Hartley Act allows the U.S. President to temporarily bar national emergency strikes and imposes various restrictions on labor unions.
Step-by-step explanation:
The Taft-Hartley Act, passed by Congress over President Truman's veto in 1947, is the legislation that allows the U.S. President to temporarily bar national emergency strikes. This act placed significant restrictions on labor unions' powers, including the elimination of rules mandating that workers join unions, as well as the requirement that labor leaders give advance notice before calling a strike. Furthermore, the Taft-Hartley Act was used in more recent times when President Obama threatened its invocation during the longshoremen's work stoppage in 2002, proving its continued relevance in labor management relations.