Different Idea: The Red Menace.
Suppose that the Soviets handedly defeated Poland in the Polish-Soviet War of the 1920s. As Poland is forcibly reintegrated into the Soviet Sphere of Influence, Reds continue to gain across Europe. In Hungary, Bela Kun emerges as a communist leader--a situation that is loudly supported by the Soviet Union and therefore likely to prevail.
The Treaty of Versaillies had greatly weakened Germany, and the 1923 occupation of the Rhineland threatened to push the Republic into the Communist Camp. KPD leader Ernst Thallmann spoke of a New Order--and was a rising star, not least of all because the General Secretary of the Soviet Union--Leon Trotsky--was loudly seeking a world revolution.
By 1926, the Weimar Republic was failing. The Continued Occupation of the Rhineland had led to German Hyperinflation and Strong Gains of the KPD. At this point, the Western Allies were forced to see the writing on the wall--that the huge push for reparations were very likely to create a second communist power. And in Moscow, Leon Trotsky was doing all he could to get exactly that.
Including Staging a Coup.
With the Red Army Massing on the German Border, Trotsky made a deal with Thalmann--lead the revolution and the Red Army will pave the way. This was the Allies Worst Nightmare--but thanks to their previous abuses against Germany, there was little they could do to Support the failing German State. They certainly would not throw their own armies to support German Democracy, although they would respond with the harshest words they could.
There was considerable resistance to the Communist Coup. Much of the Army rallied under Von Hindenburg's exhortations to defend the Fatherland. In Bavaria, the National Socialists under Ernst Rohm would attempt to fight the Communist Uprising. But these efforts were doomed. Thanks to the artifically small size of their army and the large amounts of Germany that simple fell without a fight, the defeat of the Weimar Republic was a matter of time--and of months, not years. On May 1st, 1927, Ernst Thallmann celebrated May Day with special importance--the last pockets of German Resistance in the German Alps had surrendered. And there would be sensational show trials to follow--Paul Von Hindenburg was sentenced to death but this was commuted to Life imprisionment. Adolf Hitler and Ernst Rohm were executed, as were many of the ringleaders of the Reichswehr that had attempted to resist the Coup.
The Western World could only gape in amazement at the rising power of the political left. But the worst blow would be soon to come. On June 16th, 1929, the US Stock Market crashed. For the past four years, it had been pumped up by poorly financed credit and purchases on Margins. But Consumer confidence had simply faded--and in three weeks, the stock market lost half of its value.
Three Years Later, Western Democracies were failing. Maurice Thorez of France had been approached much the same way as Thalmann had six years before, and with similar results, except that now it was Thalmann who would be doing the supporting. With the German Worker's Liberation Army now a battletested force with the support of the Red Army in its wings, Germany was out to repeat the same strategy to France that the Soviets had done to Germany.
The United Kingdom, suffering from the Depression, could only sit and watch as the French Communists overthrew Pierre Laval, but this time there would be no Civil War. The Third Republic had already bled its own dry from the first world war, and while there was some resistance to the takeover, it was little more than elements of the French Right fleeing to other countries, such as Italy and the UK.
With France a Communist Ally, much of Europe was pressured into the Communist Camp--President Benes of Czechloslovkia was outright bullied into offering army bases for the Worker Liberation Army, and Romania would fall into the hands of the Soviets.
Italy and Spain found themselves allying against the rising red tide, and bringing Greece, Austria and Yugoslavia on board as well. The United Kingdom had been marginalized in Europe not by a state but an ideology, and Italy now appeared to be the great bastion against Communism.
This Tension built for a full Decade. Spain quashed a Republician Coup attempt and the Kind remained in control, even though the attempt needed Italian troops to put down the rebellion. Engelbart Dolfuss of Austria was murdered by Communist Radicals, but Italy's military posturing ensured that Kurt Schussnigg would be his successor.
Finally, there would be a flashpoint: 1938. The Death of Mustafa Kemal Ataturk in Turkey left the job to Ismet Inonu, but the position of Turkey was crucial in world politics. Inonu would grudgingly choose the communists--on a deal that would guarantee Soviet Access through the Bosporus and would guarentee the Eastern Borders of the Country. Seeing the opportunity, the Communists would push into Bulgaria in the attempt to control the Black Sea entirely. This move would be resisted by Greece, who quickly deployed elements of their army into Sofia and attempted to hold out against the Romanian-Soviet Attack.
And this flashpoint would eventually signal the end of a cold war between Fascists and Communists. The German Worker's Liberation Army would smash right into Austria, fighting Austria and Italy through the Alps. France would also join the fighting, it also smashing into Italian Alps.
It would be a long, drawn out war, a war fought without the awesome Panzer doctrine of OTL. But the Fascists would be beaten in a circle. First Bulgaria would fall, followed by Austria. Yugoslavia and Greece would put up a hard fight, but they would also fall. It would be Spain and Italy that would very difficult to crack. But Five Years of War would eventually crack even these nations. Italy had been forced back to the Po River through heavy fighting, but the German Campaign of 1943 would smash the Messe Line and lead to the quick fall of Rome and Italy's surrender. In Spain, a similar situation arose on the outskirts of Madrid--the Spanish built solid defensive lines, but once these were broken the nation could not survive in the face of numerical and technical superiority.
In light of these events, It seems obvious that the creation of the Anglo-American Alliance, and their successful effort to include Japan in their arrangements would be in the cards. It would be on this basis that the Allies would unite against Communism. But the development of the Atomic Bomb in 1952, followed by the H Bomb in 1960, would indicate that this would be an ideological war without all-out fighting. And the fall of Communism, although a miracle when it began with the Polish Uprising of 1998, was based ultimately on the failure of nations to meet their own people's needs. When Ernst Thalmann died in 1964, he was celebrated as a hero, just as Leon Trotsky had been three years earlier. But the people who followed weren't heroes--they were corrupt exploiters who did nothing as their own economic situations stagnated and began to fall. Their legacy remains heavy on the world today, with endless numbers of starving French Children and millions of immigrants from various German States and Eastern Europe.
To some degree, its an open question what victory Thalmann won. Ideological Hedgemony to be sure, but in the end it didn't work out that way.