He strongly encouraged the United States to take a vigorously anti-Communist foreign policy in the early years of the Cold War. He was a leading advocate for British combat operations in the Korean War. Two of the key institutions of the post-war world, the North Atlantic Treaty Organisation (NATO) and the Marshall Plan for aid to post-war Europe, were in considerable part the result of Bevin's efforts during these years. This policy, little different from that of the Conservatives ("Hasn't Anthony Eden grown fat?" as wags had it), was a source of frustration to some backbench Labour MPs, who early in the 1945 Parliament formed a "Keep Left" group to push for a more Left-Wing foreign policy.