Comment: Interestingly, President Carter issued the following directive during the 1980 Iranian hostage crisis:

Secretary of Treasury [State] and the Attorney General will invalidate all visas issued to Iranian citizens for future entry into the United States, effective today. We will not reissue visas, nor will we issue new visas, except for compelling and proven humanitarian reasons or where the national interest of our own country requires. This directive will be interpreted very strictly.