"Unless we can achieve this objective in South Vietnam, almost all of Southeast Asia will probably fall under Communist dominance (all of Vietnam, Laos, and Cambodia), accommodate to Communism so as to remove effective U.S. and anti-Communist influence (Burma), or fall under the domination of forces not now explicitly Communist but likely then to become so (Indonesia taking over Malaysia). Thailand might hold for a period without help, but would be under grave pressure. Even the Philippines would become shaky, and the threat to India on the West, Australia and New Zealand to the South, and Taiwan, Korea, and Japan to the North and East would be greatly increased" - National Security Action Memorandum 288, March 17, 1964
In LSAT language, this is what is referred to as a "circular argument". In a circular argument, the premise is left to assumption. One can assume that the "Domino theory", or China's or the Soviet Union's sphere of influence may be at the forefront of one's thoughts upon reading this memorandum. However, none of that can be directly inferred from this document. So, what premise to this argument is a reader supposed to summon in order to fully understand a memorandum of this magnitude? And for a document as consequential as this, is it safe to assume?