On January 4, 1980, the President Carter announced an embargo on grain exports to the Soviet Union in response to the Soviet armed invasion of Afghanistan. The embargo was designed to limit U.S. grain exports to the Soviet Union to 8 million metric tons, an amount to which the United States was committed under the 1975 five-year grain sale agreement. Following the embargo, U.S. Department of Agriculture officials estimated that the Soviets would be unable to import more than 22 million metric tons of grain from all sources. The embargo has been in effect long enough to measure its effectiveness in restraining U.S. grain exports and reducing Soviet grain imports.