President Barack Obama signed a law on Friday that effectively bars an Iranian diplomat from serving as an envoy at the United Nations because of suspicions he was involved in the 1979-81 Tehran hostage crisis. Obama signed a law passed by the U.S. Congress that blocks any individual from entering the United States who has been found to have been engaged in espionage or terrorist activity against the United States or if that person may pose a threat to U.S. national security. The United States had already said it would not grant a visa to Iran’s proposed U.N. ambassador, citing the envoy’s links to the 1979-1981 hostage crisis. Obama had come under strong pressure not to allow Hamid Abutalebi into the country to take up his position in New York. The U.S. government objects to Abutalebi because of his suspected participation in a Muslim student group […]