Sometimes I wonder about the people who think up names for military and espionage operations. Sometimes those names are perfect.

Like Unthinkable.

It’s April 1945. The Allies sweep into Germany on two fronts, racing toward Berlin. The German capitol could’ve been the scene of a catastrophic clash of west and east if both sides had insisted on the prestige of taking the city. But the Americans wanted to avoid a confrontation with Moscow, and the Red Army was the first to raise its flag over Berlin.

This seemed to form part of a rude awakening for Winston Churchill. He’d assumed the Soviets would end the war weaker than American and British forces. But the Red Army had rolled over eastern territories, greatly expanding its sphere of influence. Above all, Poland had slipped into this Russian net. Britain’s responsibility for defending Poland’s sovereignty was a basis for entering the war to begin with. How could Britain stand by and let the Russians finish what the Germans started?

Mix this with Churchill’s anticommunism, and the unthinkable — a third world war directly after the second — was actually considered.

Churchill asked the Chiefs of Staff to draw up a plan to advance forces east against their old ally, the Soviet Union. It would have to be a surprise attack, because the staff recognized this would be the West’s only advantage in the face of Soviet strength.

Even more unthinkable, the plan called for German Wehrmacht troops to fight alongside the West. About 2 million Germans had surrendered to British custody. Some units weren’t disbanded; they were renamed Dienstgruppen (service groups) and used for labor. Confiscated weapons weren’t immediately destroyed. Some were stockpiled, while others were destroyed after a lag time that puzzled German soldiers held prisoner but with full kits and equipment. As one ex-soldier recalled, they could have started another war.

British planners concluded the whole idea was too big a risk. The Red Army was too strong, and the political fall out of an offensive war was too large. With a few exceptions such as the notoriously bellicose General Patton, the Americans weren’t interested in continuing a military advance into eastern Europe (at that time). In Britain, public opinion wouldn’t be on Churchill’s side. The Russians were still considered an ally that fought heroically against a common enemy.

So Operation Unthinkable never got off the ground. An active, hot war between west and east was discarded for a cold one that might not be as finished as we thought it was.

If you understand German, check out this video that summarizes Operation Unthinkable. The British historian Dr. Christopher Knowles (congrats on the PhD!) summarized the operation a few years ago on his excellent blog.