((a)) ** Duty of Secretary** The Secretary shall, whenever he finds that a plan or any provision thereof obstructs or does not tend to effectuate the declared policy of this chapter, terminate or suspend the operation of such plan or such provision thereof.

((b)) ** Referendum** The Secretary may conduct a referendum at any time and shall hold a referendum on request of the board or of 10 per centum or more of the potato producers, or of the total number of producers and importers when importers are subject to a plan, to determine if potato producers and importers favor the termination or suspension of the plan, and he shall terminate or suspend such plan at the end of the marketing year whenever he determines that such suspension or termination is favored by a majority of those voting in a referendum, and who produce and import more than 50 per centum of the volume of the potatoes produced and imported by those voting in the referendum.

((c)) ** Limitation** The termination or suspension of any plan, or any provision thereof, shall not be considered the issuance of a plan within the meaning of this chapter.