No other foreign policy adviser would exercise House's almost exclusive influence over presidential decision making until Henry Kissinger, save perhaps Franklin D. Roosevelt's Harry Hopkins. In some ways, Hopkins's relationship to Roosevelt resembled that of House to Wilson, whom Roosevelt had served as a rather free-floating assistant secretary of the navy. By 1941, as Hopkins's biographer Robert E. Sherwood explained it: "The extraordinary fact was that the second most important individual in the United States government…had no legitimate official position nor even any desk of his own except a card table in his bedroom. However, the bedroom was in the White House." To the recently defeated Republican candidate, Wendell Willkie, who had asked why the president kept so close to him a man widely distrusted and resented, Roosevelt replied: "I can understand that you wonder why I need that half man around me. But someday you may well be sitting here where I am now as president of the United States. And when you are, you'll be looking through that door over there and knowing that practically everybody who walks through it wants something out of you. You'll learn what a lonely job this is, and you'll discover the need for somebody like Harry Hopkins who asks for nothing except to serve you."
During his unprecedented three-plus terms as president, of course, Roosevelt had hundreds of advisers. But none wielded more than a transitory and peripheral influence on foreign policy, while Hopkins's brilliant talent for getting things done was exercised with authority throughout the government and the coalition against Germany and Japan. Sherwood described Hopkins's service thus: "Hopkins made it his job, he made it his religion, to find out just what it was that Roosevelt really wanted and then to see to it that neither hell nor high water, nor even possible vacillations by Roosevelt himself, blocked its achievement."
But Hopkins was not without convictions of his own, although they usually coincided with those of the president. Eleanor Roosevelt once wrote that Hopkins "gave his opinions honestly, but because Franklin did not like opposition too well—as who does—he frequently agreed with him regardless of his own opinion, or tried to persuade him in indirect ways." But Hopkins could intervene directly. Once, when Roosevelt was unable to join Winston Churchill and Joseph Stalin at a conference because of the 1944 election, he was about to send Churchill a cable implying that the prime minister could speak for him. Hopkins ordered the cable to be held and rushed to get Roosevelt to cancel it, which Roosevelt did. Hopkins had the respect of Stalin, who spoke to him with "a frankness unparalleled in my knowledge in recent Soviet history," according to the American ambassador to Moscow, Averell Harriman, and the respect and deep affection of Churchill, who dubbed him "Lord Root of the Matter" and talked feelingly to Sherwood of "the great heart that is within that frail frame." Hopkins successfully supported Churchill in persuading Roosevelt that France had to share in the postwar occupation of Germany, and he often toned down the president's communications with the haughty General Charles de Gaulle.
Roosevelt and Hopkins last saw each other after the Yalta Conference, when Hopkins, too ill to return home by ship with the president, flew back to enter the Mayo Clinic, where he was still hospitalized when Roosevelt died. He returned to Washington to brief the new president, Harry Truman, who later recalled that "I hoped that he would continue with me in the same role he had played with my predecessor." Hopkins undertook one more mission to Moscow and succeeded in obtaining Russian concessions that opened the way to the United Nations founding conference at San Francisco, but he was too sick to continue. Six months later he was dead, leaving behind another fascinating historical "if": How differently would subsequent Soviet-American relations have developed if Hopkins could have fulfilled the wish of President Truman?