Negotiations for the preliminary agreement would be conducted under a new process, which the State Department, employing classic bureaucratic jargon, called “the selective nuclear-multilateral approach.” In preliminary discussions held in July 1945, the Canadians had proposed this method of negotiations led by a small group of influential nations — which effectively became the model for multilateral trade negotiations for the remainder of the twentieth century — as a compromise between the strictly bilateral approach, which had been favored politically by FDR and Cordell Hull, and the broader multilateral approach the British insisted upon. The Americans believed they were constricted by the requirements of the Reciprocal Trade Agreements Act specifically, and by political realities in Congress more generally, to negotiating bilaterally on select tariffs on an item-by-item basis.
That is from the new and highly useful and still under-discussed book The Wealth of a Nation: A History of Trade Politics in America, by C. Donald Johnson, Oxford University Press. I am happy to second Doug Irwin’s blurb: “This splendid book covers the politics of American trade policy from the country’s beginnings through Trump. Johnson provides a great overview of a fascinating subject.”