The Hess Agreement, known informally as "the big switch", was a diplomatic agreement among the governments of Germany, United Kingdom, and France entered into in the summer of 1940. The Agreement ended the first phase of the Second World War and realigned the balance of power in Europe heavily in Germany's favor. The agreement was named for Rudolf Hess, the Deputy Führer of Germany, who initially brought the proposal to the British government with Adolf Hitler's blessing.
Germany had been engaged in a two-front war since the winter of 1938-9, when Hitler accepted an invitation from the government of the heretofore neutral Poland to assist in defending that country against Soviet invasion, while his forces were already committed to a general invasion of France. The Hess Agreement represented Germany's effort to extricate itself from a two-front war by resolving its differences with its major enemies along its western flank.
The governments of Britain and France welcomed the opportunity to redirect Germany's belligerence towards the east. The war had stalemated very early on in a depressing parallel to the First World War. Britain and France's respective populations were increasingly dissatisfied with the ongoing attacks Germany was able to inflict even as there were no breakthroughs on the battlefield. Additionally, the agreement brought Britain, France and Germany into an alliance to help defend Poland and to invade the USSR itself; the governments of both Prime Minister Neville Chamberlain and Premier Edouard Daladier found Soviet Communism more frightening than German Nazism.
In addition to gaining Britain and France as allies, the Agreement was very beneficial to Germany in other ways. Germany was required to withdraw all its troops from French territory; however, it continued to occupy erstwhile Anglo-French allies Luxembourg, the Netherlands, Belgium, Denmark, and Norway. Germany also continued to occupy Czechoslovakia, the invasion of which had been the Westerners' initial casus belli.
The British and French also stopped supporting the Second Spanish Republic in the Spanish Civil War, though they maintained diplomatic relations with the Republic and did not support the Nationalist side.
In Britain, the Hess Agreement was highly controversial politically, opposed not only by the Liberal and Labour Parties, but by a sizable minority of Neville Chamberlain's fellow Conservatives as well. Initially, opposition was led by War Minister Winston Churchill. After Churchill's untimely (and, to many, suspicious) death, internal opposition was led by Churchill ally Ronald Cartland. Still, Chamberlain survived several confidence votes after the Agreement was ratified. His eventual successor, Sir Horace Wilson, also survived confidence votes himself, but adopted several authoritarian tactics in early 1941 to keep his hold on power. These actions alienated civilians and the military alike.
The Agreement was also divisive in the British military. Few military personnel welcomed the switch; many accepted it grudgingly, out of a sense of duty to follow any lawful order. Others resigned from the service in protest, including Alistair Walsh, who held the distinction of having captured Rudolf Hess when he first landed unexpected in the UK, near Dundee, Scotland. Some of those who resigned were offered the opportunity to reenlist conditionally, provided they would never be ordered into a position where they would fight alongside German soldiers or serve under German officers directly.
In the French military, Hess Agreement's popularity largely fell along rank lines. Many French generals were staunch anti-Marxists and were excited for the opportunity to go to war against the Soviets. The move was less popular among the lower ranks, especially among socialists. However, open opposition was less common, at least initially.
End of the Agreement
While the German-led coalition was able make gains into Soviet territory throughout the fall of 1940, the Agreement began to fall apart the following year. In the spring of 1941, the British military finally had had enough of Horace Wilson's authoritarianism, and overthrew him in an almost unprecedented coup. The new military government withdrew its troops from Soviet soil and went back to war with Germany. France remained in the agreement throughout the summer of 1941, but Daladier began taking steps to renew war with Germany, which included renewed supplies to the Spanish Republicans, the expansion of the Maginot Line, and finally, a complete withdrawal from Soviet territory in the winter of 1941.