The Treaty of Versailles proved a disaster, at once too harsh and too soft. Its terms were far less punitive than those the victorious Allies would dictate to Germany after World War II. Earlier, Germany itself had demanded tougher concessions from a defeated France in 1871 and Russia in 1918.
In the end, the Allies proved unforgiving to a defeated Germany in the abstract, but not tough enough in the concrete.
One ironic result was that the victorious but exhausted Allies announced to the world that they never wished to go to war again. Meanwhile, the defeated and humiliated Germans seemed all too eager to fight again soon to overturn the verdict of 1918.
The consequence was a far bloodier war that followed just two decades later. Eventually, “the war to end all wars” was rebranded “World War I” after World War II engulfed the planet and wiped out some 60 million lives.
.. For an enemy to accept defeat, it must be forced to understand why it lost, suffer the consequences of its aggressions — and only then be shown magnanimity and given help to rebuild.
.. Had the Allies continued their offensives in the fall of 1918 and invaded Germany, the peace that followed might have more closely resembled the unconditional surrender and agreements that ended WWII, leading to far more than just 20 years of subsequent European calm.
Deterrence prevents war.
Germany invaded Belgium in 1914 because it was convinced that Britain would not send enough troops to aid its overwhelmed ally, France. Germany also assumed that isolationist America would not intervene.
Unfortunately, the Allies of 1939 later repeated the errors of 1914, and the result was WWII.
Germany currently dominates Europe, just as it did in 1871, 1914, and 1939. European peace is maintained only when Germany channels its enormous energy and talents into economic, not military, dominance. Yet even today, on matters such as illegal immigration, overdue loans, Brexit, and trade surpluses, Germany tends to agitate its allies.