Notwithstanding any other provision of this Act, price support at a level in excess of the maximum level of price support otherwise prescribed in this Act may be made available for any agricultural commodity if the Secretary determines, after a public hearing of which reasonable notice has been given, that price support at such increased level is necessary in order to prevent or alleviate a shortage in the supply of any agricultural commodity essential to the national welfare or in order to increase or maintain the production of any agricultural commodity in the interest of national security. The Secretary’s determination and the record of the hearing shall be available to the public.