 This testimony was considered an important factor in formulating what became known as the Truman Doctrine, which stated that the U.S. would support Greece and Turkey with economic and military aid to prevent their falling into the Soviet Union's sphere of influence.MacVeagh pressed the post-war Greek Government to pursue a democratic policy.While he was in Greece, MacVeagh conducted excavations beneath the Acropolis and made archeological contributions to the National Archaeological Museum of Athens.