In November of 1918, the Allied Powers ended World War One by signing an Armistice agreement with the remaining belligerents. At this point, the German army was loosing territory at a rate of miles a day, and the Americans were finally beginning to devote their full industrial and demographic resources to the war effort. Despite the collapse of the Eastern Front and the withdrawal of the Russian Empire in March of 1918, the Italians had the Austrians on the rope and the British were successfully chasing the Ottomans out of the Levant and Mesopotamia.
So why did the Allies agree to an armistice that left their enemies intact at the very time when they were finally in a position to crush them once and for all?
Reading Hew Strathan's The First World War, I couldn't help but feel that by agreeing to an armistice, the French and British were literally snatching defeat from the Jaws of victory. But clearly the Allied leadership of had different priorities back in 1918. I suspect that my reading of events is influenced by the knowledge that Germany would start another massive war 20 years later, but I don't quite understand why agreeing to an armistice seemed like a good idea to the Allied leadership in late 1918.
Why did the Allies not want push on to forcibly take Berlin and like the Germans had taken Paris back in 1871?
A couple of reasons that all mesh together:
There were talks early on about breaking up Germany but it quickly became clear that wasn't feasible. Fact is is that the wealthiest part of France, industrially at least, was occupied and sacked for four years. Belgium as a whole was destroyed. They needed a central, standing German government with its industry and wealth in tact to pay reparations. The British in particular, who would go from the largest creditor to largest debtor nation in those four years, full on relied upon German industry to rebuild.
Going on longer would have made the situation in Germany more volatile. Even as it happened now Bavaria was able to secede as a Soviet Republic for a couple of months. Freikorps and revolutionaries would fight in the streets for years. Berlin was being sacked by radical socialists and communists. The more they let the situation go out of control the more likely Germany was to fracture at the seams. That was not beneficial to anyone.
Ultimately the war goals of the Allies were simple. Push the Germans out of the lands they occupied and maybe seize Alsace-Lorraine back. Use German reparations to rebuild the damage. Neuter their military so that they may not do what they did again. Break them up enough so that they are contained but not so much that the economy of the world falls into pieces (Germany was the #3 GDP in the world). Lastly enforce a democracy so that the aristocracy may not start shit again.
All of that was achieved. The German leadership realized they were lost. The aristocracy across the nation stepped down including the Kaiser and Emperor. The armies completely surrendered. Polish nationalist groups especially were up in arms and would secede along with the lands given to them thus creating an Eastern contender. Reparations would be put in action and the German army was not to exceed 100,000 men. Now obviously the reparations would hardly be enforced and the restriction on the army was de jure but not de facto but that's not on the men fighting and the men who put in place the terms but those who were there to enforce it after.
Honestly, what would it have achieved? Let me reiterate: Berlin had fallen to revolutionaries. The armies were surrendering. The navy was in full mutiny. Places in Germany were already seceding and everywhere else revolution was in full swing. The aristocracy was stepping down officially and even fleeing. What other purpose was there to continue pushing on? Germany was accepting unconditional, total surrender.
Marshal Foch (Commander-in-Chief of the Allied Armies) answered this criticism by saying that the War was not an end in itself. The purpose of war is to impose your will on the enemy, not fighting for its own sake. The German Army had been defeated in the field, that is why they had requested an armistice. The Allies had successively imposed their will on the Germans; what was the point in carrying on the bloodshed by fighting all the way to Berlin? To demonstrate that the German Army had been defeated? They were already defeated by November 1918, this is why they sued for peace.
Now, you could say that the mistakes came after the armistice, in the peace treaty. This is what Foch claimed, that it was Versailles that robbed the Allies of their victory, not the armistice.
Source: Raymond Recouly, Marshal Foch: His Own Words on Many Subjects (London: Thornton Butterworth, 1929).
Amongst the other reasons, the French and British were exhausted and to continue into Germany may have led to greater dominance of the United States in the final negotiations at the expense of the French and British. I think the armistice really shocked them, and they took a chance to end the war.