Notwithstanding any other provision of law, whenever the President determines it is in the United States national interest, he shall furnish assistance under this chapter or shall furnish defense articles or services under the Foreign Military Sales Act [
22 U.S.C.
2751 et. seq.], pursuant to an agreement with the recipient of such assistance, articles, or services which provides that such recipient may only obtain such assistance, articles, or services in exchange for any necessary or strategic raw material controlled by such recipient. For the purposes of this section, the term “necessary or strategic raw material” includes petroleum, other fossil fuels, metals, minerals, or any other natural substance which the President determines is in short supply in the United States.