Remilitarization of the Rhineland
The 1919 Treaty of Versailles forbade the defeated Germans from stationing armed forces in the Rhineland – a region in western Germany bordering France, Belgium, and the Netherlands – and expressly specified that a violation “in any manner whatsoever… shall be regarded as committing a hostile act“. The demilitarized Rhineland was the single greatest guarantor of peace in Europe because it made it impossible for Germany to attack her western neighbors.
Simultaneously, because it left Germany defenseless on her western borders, it made it impossible to attack her eastern neighbors because doing so would leave her open to a devastating attack from those eastern neighbors’ ally, France, on Germany’s unprotected west.
While a demilitarized Rhineland was positive for European peace, it was a humiliating negative for German pride, and one of Hitler’s most popular campaign promises during the Nazis’ rise to power was to remilitarize the Rhineland. In 1936, Hitler decided to send soldiers into the Rhineland – a huge risk, considering that the German military at the time was in no condition to do anything other than beat a humiliating retreat if the Western Allies had opposed the remilitarization with even minimal armed force. Hitler however gambled that while the Western Allies had the power to thwart him, they lacked the will to actually use that power.
On March 7, 1936, against the advice of his generals, Hitler ordered 19 German battalions to occupy the Rhineland, in direct violation of the treaties of Versailles and Locarno. He won the gamble: the British and French protested, but neither took direct action to enforce the treaties’ terms. Having taken the measure of France and Britain, Hitler’s appetite was whetted for ever riskier gambles in which he calculated that he could act egregiously, secure in the knowledge that the Western Allies would strongly protest and vehemently condemn, but stop short of direct action. He kept escalating until his invasion of Poland in 1939, when he was stunned that Britain and France had finally had enough and declared war.