Various messengers from the "Widerstand" movements had arrived in Britain in 1938-39 stating if only Britain abandoned appeasement, then the leaders of the Wehrmacht would stage a "putsch" to depose Hitler rather than fight a war with Britain again. In August 1939, the British government repeatedly warned Germany that an attack on Poland would cause a war with Britain, in part out of the hope that the Wehrmacht would indeed overthrow Hitler rather than risk another world war. On 1 September 1939, Germany invaded Poland and on 3 September 1939, Britain declared war on Germany. Despite the promises of numerous messengers, the Wehrmacht stayed loyal to Germany, continued on with the conquest of Poland, and made no effort to depose Hitler. The fact that the Wehrmacht stayed loyal to Hitler in 1939 in spite of all the promises from anti-Nazi Germans that it would not if only Britain made a firm stand against Hitler did much to discredit the "Widerstand" movement in British eyes and much of Trott's difficulty in enlisting British support was due to this fact. A friend of Weizsäcker, Trott formally joined the "Auswärtiges Amt" in 1939 at his suggestion after having worked for the "Auswärtiges Amt" as a researcher on China for the previous two years . In October 1939, Trott went to the United States to attend a conference of the Institute of Pacific Relations in Virginia Beach in November 1939. On his way to the United States, Trott was almost interned in Gibraltar as an enemy alien where his ship had stopped, but was able to persuade the British officials that he was an Afrikaner from South Africa, using his Balliol tie as proof that he attended Balliol College (which was true), which meant he could not be a German (which was not). He also visited Washington, D.C. in October of that year in an unsuccessful attempt to obtain American support. He met with Roger Baldwin, Edward C. Carter, William J. Donovan, and Felix Morley of "The Washington Post". During the conference in Virginia Beach, Trott met numerous members of the business and academic worlds of the United States and Canada who were interested in China. Wheeler-Bennett, who owned an estate in Virginia and shared Trott's interests in Sinology, also attended the conference in Virginia Beach. Wheeler-Bennett wrote: "In the plenary sessions and committees of the conference, von Trott observed a very 'correct' attitude.