"The use of economic sanctions to stem weapons proliferation acquired a new dimension in the 1990s. While earlier legislation required the cutoff of foreign aid to countries engaged in specified nuclear proliferation activities and mentioned other sanctions as a possible mechanism for bringing countries into compliance with goals of treaties or international agreements, it was not until 1990 that Congress enacted explicit guidelines for trade sanctions related to missile proliferation. In that year a requirement for the President to impose sanctions against U.S. persons or foreign persons engaging in trade of items or technology listed in the Missile Technology Control Regime Annex (MTCR Annex) was added to the Arms Export Control Act and to the Export Administration Act of 1979. Subsequently, Congress legislated economic sanctions against countries that contribute to the proliferation of chemical, biological, and nuclear weapons in a broad array of laws. This report offers a listing and brief description of legal provisions that require or authorize the imposition of some form of economic sanction against countries, companies, or persons who violate U.S. nonproliferation norms. For each provision, information is included on what triggers the imposition of sanctions, their duration, what authority the President has to delay or abstain from imposing sanctions, and what authority the President has to waive the imposition of sanctions."