“The generally accepted image of international trade is one in which a number of trading communities... are engaged in striving each to win for itself, and at the expense of the others, the largest possible share of a strictly limited objective—the world market. ... So far as world or international trade is rightly presented as a competitive process, that competition takes place not between America, Britain, Germany, but between a number of separate American, British, German, firms. The immediate interests of these firms is not directed along political lines.”