Remilitarisation of the Rhineland
The remilitarisation of the Rhineland began on 7 March 1936, when military forces of Nazi Germany entered the Rhineland, which directly contravened the Treaty of Versailles and the Locarno Treaties. Neither France nor Britain was prepared for a military response, so they did not act. After 1939, commentators often said that a strong military move in 1936 might have ruined the expansionist plans of Adolf Hitler, the dictator of Germany. However, recent historiography agrees that both public and elite opinion in Britain and France strongly opposed a military intervention, and neither had an army prepared to move in.
After the end of World War I, the Rhineland came under Allied occupation. Under the 1919 Treaty of Versailles, the German military was forbidden from all territories west of the Rhine or within 50 km east of it. The 1925 Locarno Treaties reaffirmed the then-permanently-demilitarised status of the Rhineland. In 1929, German Foreign Minister Gustav Stresemann negotiated the withdrawal of the Allied forces. The last soldiers left the Rhineland in June 1930.
After the Nazi regime took power in January 1933, Germany began working towards rearmament and the remilitarisation of the Rhineland. On 7 March 1936, using the Franco-Soviet Treaty of Mutual Assistance as a pretext, Hitler ordered the Wehrmacht to march 20,000 German troops into the Rhineland, which caused joyous celebrations across Germany. The French and the British governments, unwilling to risk war, decided against enforcing the treaties.
The remilitarisation and the German rearmament changed the balance of power in Europe from France and its allies towards Germany by allowing Germany to pursue a policy of aggression in Western Europe that had been blocked by the demilitarised status of the Rhineland.
The fact that Britain and France did not intervene made Hitler believe that neither country would get in the way of Nazi foreign policy. That made him decide to quicken the pace of German preparations for war and the domination of Europe. On 14 March 1936, during a speech in Munich, Hitler stated, "Neither threats nor warnings will prevent me from going my way. I follow the path assigned to me by Providence with the instinctive sureness of a sleepwalker".
Background
Versailles and Locarno
Under Articles 42, 43 and 44 of the 1919 Treaty of Versailles, which was imposed on Germany by the Allies after World War I, Germany was "forbidden to maintain or construct any fortification either on the Left bank of the Rhine or on the Right bank to the west of a line drawn fifty kilometers to the East of the Rhine". If a violation "in any manner whatsoever" of the article took place, it "shall be regarded as committing a hostile act... and as calculated to disturb the peace of the world". The Locarno Treaties, signed in October 1925 by Germany, France, Belgium, Italy and Britain, stated that the Rhineland should continue its demilitarised status permanently. Locarno was regarded as important by being a voluntary German acceptance of the Rhineland's demilitarised status, as opposed to the Diktat of Versailles. Locarno's terms had Britain and Italy vaguely guarantee the Franco-German and Belgian-German borders and the continued demilitarised status of the Rhineland against a "flagrant violation". A German attack on France required Britain and Italy to go to France's aid under Locarno, and a French attack on Germany required Britain and Italy to come to Germany's aid. The American historian Gerhard Weinberg called the demilitarised status of the Rhineland the "single most important guarantee of peace in Europe" by preventing Germany from attacking its western neighbours and, since the demilitarised zone rendered Germany defenseless in the West, by making it impossible to attack its eastern neighbours by leaving Germany open to a devastating French offensive if the Germans tried to invade any state guaranteed by the French alliance system in Eastern Europe, the cordon sanitaire.The Versailles Treaty also stipulated that Allied military forces would withdraw from the Rhineland by 1935. The British delegation at the Hague Conference on German war reparations proposed decreasing the amount of money paid by Germany in reparations in exchange for the British and French forces evacuating the Rhineland. The last British soldiers left in late 1929, and the last French soldiers left in June 1930.
As long as the French continued to occupy the Rhineland, it functioned as a form of "collateral" under which the French could respond to any German attempt at overt rearmament by annexing the Rhineland. Once the last French soldiers left the Rhineland in June 1930, it could no longer play its "collateral" role, which opened the door for German rearmament. The French decision to build the Maginot Line in 1929 was a tacit French admission that it would be only a matter of time before German rearmament on a massive scale would begin sometime in the 1930s and that the Rhineland was going to be remilitarized sooner or later. Intelligence from the Deuxième Bureau indicated that Germany had been violating Versailles throughout the 1920s with the considerable help of the Soviet Union. With the French troops out of the Rhineland, Germany could be expected to violate Versailles only more openly. The Maginot Line, in turn, lessened the importance of the Rhineland's demilitarised status from the view of French security.
Foreign policy
The foreign policy of Fascist Italy was to maintain an "equidistant" stance from all the major powers and to exercise the "determinant weight" with which the power Italy chose to align would decisively change the balance of power in Europe. The price of such an alignment would be support for Italian ambitions in Europe and/or Africa.The foreign policy goal of the Soviet Union was set forth by Joseph Stalin in a speech on 19 January 1925 that if another world war broke out between the capitalist states, "We will enter the fray at the end, throwing our critical weight onto the scale, a weight that should prove to be decisive". To promote that goal, the global triumph of communism, the Soviet Union tended to support German efforts to challenge the Versailles system by assisting the secret rearmament of Germany, a policy that caused much tension with France.
An additional factor in Franco-Soviet relations was the Russian debt issue. Before 1917, the French had been by far the largest investors in Imperial Russia and the largest buyers of Russian debt. Thus, the decision by Vladimir Lenin in 1918 to repudiate all debts and to confiscate all private property owned by Russians or foreigners, had hurt French business and finance quite badly. The questions of both the Russian debt repudiation and of compensation for French businesses that had been affected by Soviet nationalisation policies poisoned Franco-Soviet relations until the early 1930s.
The cornerstone of interwar French diplomacy had been the cordon sanitaire in Eastern Europe, which was intended to keep both the Soviets and the Germans out of Eastern Europe. France had thus signed treaties of alliance with Poland in 1921, with Czechoslovakia in 1924, with Romania in 1926 and with Yugoslavia in 1927. The cordon sanitaire states were intended as a collective replacement for Imperial Russia as France's chief eastern ally and emerged as areas of French political, military, economic and cultural influence.
It had always been assumed by the states of the cordon sanitaire that a German attack would cause France to respond by starting an offensive into western Germany.
Before 1933, German military and diplomatic leaders viewed the Rhineland's demilitarised status as temporary, aiming to remilitarise it when diplomatically opportune. In December 1918, Germany's top generals, viewing the army as a "state within the state", sought to rebuild their military to achieve the "world power status" missed in the previous war. Throughout the 1920s and early 1930s, the Reichswehr planned for wars against France and Poland, anticipating Rhineland's remilitarisation. To prepare, the government maintained barracks, secretly stored military supplies, and built versatile towers along the border.
From 1919 to 1932, British defense spending operated under the Ten Year Rule, anticipating no major wars for a decade, which severely reduced the military's capabilities. Although never outright rejected, Britain was hesitant about the "continental commitment" of deploying a large army in Continental Europe, especially against Germany, due to the heavy losses of World War I. During the Interwar Period, Britain was wary of security commitments in Eastern Europe, seeing the region as potentially drawing them into unwanted conflicts. Their readiness extended mainly to limited engagements in Western Europe.
In 1925, the British Foreign Secretary, Sir Austen Chamberlain, stated at Locarno that the Polish Corridor wasn't "worth the bones of a single British grenadier". Consequently, Chamberlain suggested the Polish Corridor's return to Germany and didn't guarantee the German-Polish border. Even their commitments at Locarno were tentative, evident by Whitehall's restriction against military discussions with Germany, France, and Italy in the event of a Locarno violation.
Overall, British foreign policy during the 1920s and 1930s favored appeasement, adjusting the Versailles-established system to Germany's benefit, hoping this would ensure peace. A key British goal at Locarno was to enable Germany's peaceful territorial ambitions in Eastern Europe, believing improved Franco-German ties would weaken France's cordon sanitaire.
Once France had abandoned its allies in Eastern Europe as the price of better relations with Germany, the Poles and Czechoslovaks would be forced to adjust to German demands and maintain peace by handing over the territories that were claimed by Germany such as the Sudetenland, the Polish Corridor and the Free City of Danzig. The British tended to exaggerate French power, and even Sir Robert "Van" Vansittart, the Permanent Under-Secretary at the Foreign Office, who was normally pro-French, wrote in 1931 that Britain was faced with an "unbearable" French domination of Europe and that a revival of German power was needed to counterbalance French power.
Whitehall little appreciated France's economic and demographic weaknesses in the face of Germany's strengths. For example, Germany had a much larger population and economy than France and had been little damaged during World War I although France had been devastated.