Cobden believed that military expenditures worsened the welfare of the state and benefited a small, but concentrated elite minority, summing up British imperialism, which he believed was the result of the economic restrictions of mercantilist policies. To Cobden and many classical liberals, those who advocated peace must also advocate free markets. The belief that free trade would promote peace was widely shared by English liberals of the 19th and early 20th century, leading the economist John Maynard Keynes (1883–1946), who was a classical liberal in his early life, to say that this was a doctrine on which he was "brought up" and which he held unquestioned only until the 1920s. In his review of a book on Keynes, Michael S. Lawlor argues that it may be in large part due to Keynes' contributions in economics and politics, as in the implementation of the Marshall Plan and the way economies have been managed since his work, "that we have the luxury of not facing his unpalatable choice between free trade and full employment". A related manifestation of this idea was the argument of Norman Angell (1872–1967), most famously before World War I in "The Great Illusion" (1909), that the interdependence of the economies of the major powers was now so great that war between them was futile and irrational; and therefore unlikely.