It is hereby declared to be the policy of the United States—
((1)) to foster and encourage the export of agricultural commodities and the products of such commodities;
((2)) not to restrict or limit the export of such commodities and products except under the most compelling circumstances;
((3)) that any prohibition or limitation on the export of such commodities or products should be imposed only in time of a national emergency declared by the President under the Export Administration Act; and
((4)) that contracts for the export of such commodities or products entered into before the imposition of any prohibition or limitation on the export of such commodities or products should not be abrogated.