A substitute amendment to Young (FL) amendment to strike the text of the bill, establishing a ban on U.S. assisted military activity in Nicaragua only if the President fails to provide Congress with a plan to interdict the flow of arms through Nicaragua to forces hostile to El Salvador. The plan must consider benefits of pursuing 1) U.S.-Nicaragua negotiations, 2) involving the OAS or UN in diplomatic or peacekeeping roles, 3) involving other countries in interdicting arms flow. The plan is replaced by the ban if Nicaragua formally agrees to cease activities against Central American or Caribbean countries and to implement certain reconstruction agreements. OAS or the President is to verify Nicaragua's compliance with the agreement. Other provisions in the bill are not included in the substitute.