For example, the victorious powers in World War I invoked the principle of self-determination, but after the dismantlement of the Austro-Hungarian Empire in 1918, the Sudetenland was incorporated into Czechoslovakia, even though its inhabitants spoke German. After the Munich Agreement in 1938, the Sudeten Germans seceded from Czechoslovakia and joined Germany, which meant that the mountainous frontier fell under German control – a terrible loss for Czech defenses.
例如，第一次世界大战的战胜国援引了民族自决原则，但是，在1918年奥匈帝国解体后，苏台徳区被并入捷克斯洛伐克，即使其居民是说德语的。在1938年慕尼黑条约之后，苏台徳区的德国人脱离了捷克斯洛伐克，加入了德国，这意味着多山的边境地区落入德国的控制之中——这对捷克的防卫来说是一个可怕的损失。