Lucy Dawidowicz attacked Barnes and contrasted his work with the German historian Fritz Fischer's book Griff nach der Weltmacht (Grasping at World Power). Barnes's very public attacks on the idea of World War I as a just war, and his thesis that the United States should not have fought in the war, won him the admiration and friendship in the 1920s of many people in the United States such Oswald Garrison Villard, the Socialist leader Norman Thomas, the critic H. L. Mencken, and the historian Charles A. Beard. Long regarded as a leader of the progressive intelligentsia, Barnes joined many of its intellectual leaders such as Beard in opposing from the left the New Deal and, at the price of their reputations, American entry into World War II. In the years following the war, he argued that Adolf Hitler did not want to go to war with the United States and that President Franklin D. Roosevelt had deliberately provoked the attack on Pearl Harbor. He also contested many aspects of the Holocaust, claiming death figures were far lower and arguing that all sides were guilty of equally awful atrocities. World War II In the late 1930s, Barnes emerged as a leading isolationist and German apologist who defended German foreign policy as a legitimate effort to overthrow the Treaty of Versailles, which Barnes regarded as monstrously unfair to Germany. In 1937, Barnes identified as a "noninterventionist" opposed to the United States being involved in any sort of foreign war. After World War II, Barnes continued to expound his pre-war views of European diplomacy. In 1939, Barnes published an article that claimed British diplomat Sir Robert Vansittart was "scheming to commit aggression" against Germany in the late 1930s. As a result, Vansittart sued Barnes for libel. In a letter to his friend Oswald Villard, Barnes said that Vansittart's libel suit against him was a "plot of the Jews and the Anti-Defamation League to intimidate any American historians who propose to tell the truth about the causes of the war". Barnes said that Louis Nizer, Vansittart's lawyer, was an "Anti-Defamation League stooge" who had "needled Vansittart into action". Barnes wrote further: If I could raise money enough for a real defense we could make this an international cause celebre, but I cannot fight the thirty million dollars now in the coffers of the Anti-Defamation League to be used for character assassination on empty