How Nazis and Communists became friends: The Molotov–Ribbentrop Pact and the start of WWII

Throughout the 1930s, Europe’s political atmosphere grew increasingly tense, caught between the forces of rising fascism and the looming threat of communism.

Under Adolf Hitler’s leadership, Germany pursued a vision of expansion, targeting lands to the east and eyeing Poland and the Soviet Union.

Driven by ideologies of racial superiority and the ambition to reclaim territories lost after World War I, Hitler’s government sought to overturn the constraints of the Treaty of Versailles by rearming Germany and reclaiming the Rhineland in 1936.

Meanwhile, the Soviet Union under Joseph Stalin was aware of Germany’s hostility toward communism, and Stalin understood that Hitler’s vision of Lebensraum, or ‘living space’, posed a direct threat to Soviet territories. 

Previously, Germany and the Soviet Union had viewed each other with mistrust.

Following the Russian Revolution of 1917, Soviet Russia represented the world’s first communist state, with policies and rhetoric condemning capitalist and fascist regimes alike.

Both nations, however, shared a certain pragmatism. In 1922, Germany and the Soviet Union had signed the Treaty of Rapallo, which reestablished diplomatic relations and allowed Germany to secretly develop and test military equipment within Soviet borders.

Despite their ideological differences, they recognized the mutual benefits of cooperation.

By the late 1930s, however, Germany’s expanding influence in Eastern Europe forced Stalin to reconsider the Soviet Union’s stance.

He feared an eventual German invasion, and with the Western powers hesitant to commit to an anti-German alliance, Stalin grew increasingly isolated. 

As Germany marched into Austria in 1938, annexing it in the Anschluss, the European balance of power teetered dangerously.

Later that year, the Munich Agreement permitted Germany to seize the Sudetenland, a region of Czechoslovakia, under the guise of protecting ethnic Germans.

Watching from Moscow, Stalin observed Britain and France’s passive response.

Convinced that the Western democracies would not intervene effectively to halt Hitler’s ambitions, Stalin recalculated his options.

Facing the likelihood of future aggression from Germany, he saw potential in a non-aggression pact that could delay conflict with the Nazis and give the Soviet Union time to strengthen its defenses. 

In the summer of 1939, German Foreign Minister Joachim von Ribbentrop arrived in Moscow.

Guided by Adolf Hitler’s instructions, Ribbentrop carried the directive to secure Soviet neutrality as Germany prepared to invade Poland.

With his polished and forceful demeanor, Ribbentrop met Soviet Foreign Minister Vyacheslav Molotov, who was Stalin’s trusted negotiator.

Molotov approached the meeting with cautious interest, aware of Stalin’s desire to avert a direct conflict with Germany while strengthening Soviet defenses.

Both men understood that any agreement would require clear terms to satisfy their respective leaders’ ambitions. 

Previously, discussions between Berlin and Moscow remained informal and tentative, as both nations assessed each other’s intentions.

Hitler, however, recognized that an agreement with Stalin would eliminate the threat of a two-front war.

Stalin, for his part, saw potential advantages in aligning with Hitler. By late August, both governments recognized that a pact could serve immediate strategic interests.

The Soviet Union would avoid confrontation, and Germany would gain the military freedom to initiate its invasion plans.  

Stalin viewed Hitler’s outreach as an opportunity to expand Soviet influence, particularly in Eastern Europe.

Molotov ensured that the discussions included precise details regarding territorial divisions. 

Eventually signed on August 23, 1939, the Molotov–Ribbentrop Pact formally established a non-aggression agreement between Nazi Germany and the Soviet Union.

Both nations pledged to refrain from supporting or participating in any action directed against each other.

By agreeing to this, Germany and the Soviet Union publicly declared their intention to remain neutral in the event of a conflict involving one another.

The pact detailed that any disagreements would be resolved through diplomatic consultations rather than military engagement.

This agreement effectively permitted Hitler to focus on his western front without fear of Soviet interference. 

In addition to the non-aggression terms, the Molotov–Ribbentrop Pact included a secret protocol that outlined specific divisions of influence within Eastern Europe.

This confidential section, unknown to the rest of the world at the time, assigned spheres of control to each signatory, allowing both Germany and the Soviet Union to expand their territorial claims.

According to the protocol, Poland was divided along the Narew, Vistula, and San rivers, with the western portion designated for German occupation and the eastern section allotted to the Soviet Union.

Furthermore, the secret protocol extended Soviet influence over the Baltic States—Estonia, Latvia, and Lithuania.

Under the terms of this clandestine agreement, Estonia and Latvia fell within the Soviet sphere, while Germany retained a limited interest in Lithuania.

Additionally, the protocol included Bessarabia, a territory that Stalin aimed to reclaim from Romania.

This provision enabled the Soviet Union to assert influence over an area it viewed as historically connected to its empire. 

In late August 1939, when news of the Molotov–Ribbentrop Pact reached Britain and France, shock and disbelief quickly spread among political leaders.

The unexpected alliance between Nazi Germany and the Soviet Union disrupted their diplomatic calculations, undermining any hope of a united front against Hitler.

Britain’s Prime Minister, Neville Chamberlain, initially struggled to grasp the full extent of the pact’s implications, but soon realized that this non-aggression agreement left Poland, Britain’s ally, defenseless against a joint German-Soviet invasion.

British leaders recognized that without Soviet support, their chances of deterring Hitler had dwindled drastically.

As a result, Britain accelerated its preparations for war, reinforcing its military resources and mobilizing diplomatic efforts to consolidate alliances with France and other countries in anticipation of conflict. 

Meanwhile, in France, the response was equally grim. French leaders, who were deeply concerned about their eastern border and the threat of German expansion, understood that the pact rendered the Soviet Union an unreliable partner.

This realization forced France to confront the reality that any coordinated effort to protect Eastern Europe against Nazi aggression now seemed futile.

The French government, pressured by a growing sense of vulnerability, began to prioritize its own defenses and accelerate the construction of the Maginot Line. French military leaders also committed to reinforcing their borders and coordinating closely with Britain. 

In Eastern Europe, smaller nations watched with acute anxiety as the Molotov–Ribbentrop Pact redrew their geopolitical landscape.

For countries like Romania, Hungary, and the Baltic States, the alliance between Germany and the Soviet Union signaled a heightened threat to their sovereignty.

Many of these nations faced growing pressure to align with either Germany or the Soviet Union, knowing that the pact had transformed Eastern Europe into a battleground for influence.

Diplomatic channels between these smaller states and Western Europe intensified as leaders sought guarantees of support.

However, the pact left these nations increasingly isolated and vulnerable. 

In early September 1939, WWII began with the German invasion of Poland began with a swift and brutal campaign.

German forces advanced from the west by using overwhelming firepower to seize Polish cities and military positions. Polish forces struggled against Germany’s well-coordinated assault.

Due to Germany’s superior technology and strategy, Polish defenses quickly fell.

On September 17, the Soviet Union, fulfilling its role under the pact’s secret protocol, invaded Poland from the east.

Caught between two powerful armies, Poland faced devastation. Within weeks, the nation was divided, its sovereignty erased as German and Soviet troops occupied the pre-agreed territories.

This led to mass displacement, with thousands of Polish civilians fleeing or being forcibly relocated, signaling the harsh reality of occupation. 

Meanwhile, the pact’s effects rippled outward, as Soviet ambitions targeted the Baltic States and Finland.

In late 1939, the Soviet Union presented these states with ultimatums demanding military bases and a Soviet military presence. Intimidated by the power of the Red Army, the Baltic governments complied, allowing Soviet forces entry.

By mid-1940, the Soviet Union formally annexed these countries. This expansion transformed the region, as Soviet political structures replaced local governments.

Estonia, Latvia, and Lithuania were incorporated into the Soviet Union, while their borders and autonomy effectively dissolved under Moscow’s control. 

Finland, however, responded differently to Soviet demands. In November 1939, motivated by the desire for territorial security and control of strategic areas, the Soviet Union launched an attack on Finland.

Known as the Winter War, this conflict revealed Finnish resilience as the smaller, well-prepared Finnish forces defended against the Soviet advance.

Although outnumbered, Finnish soldiers used their knowledge of the terrain to resist the Red Army.

After months of grueling combat, Finland ceded territory to the Soviet Union but maintained its sovereignty, which preserved its independence against tremendous odds.

This conflict strained the Soviet Union’s military resources and damaged its reputation on the world stage, yet it ultimately granted the USSR territorial gains in Karelia and other border areas. 

By late 1940, tensions began to strain the fragile pact between Nazi Germany and the Soviet Union.

As Germany secured victories across Western Europe, Hitler turned his attention eastward, eyeing Soviet territories for resources to fuel his war machine.

German ambitions focused on the fertile lands and oil reserves in Ukraine and the Caucasus.

Hitler believed that Soviet forces were weak after Stalin’s purges of the Red Army and felt increasingly confident about a rapid victory.

Secretly, German high command began planning an invasion, codenamed Operation Barbarossa, aimed at seizing Soviet territory and overthrowing Stalin’s regime. 

Meanwhile, in Moscow, Stalin attempted to maintain the pact, seeking to avoid provoking Germany.

Motivated by his awareness of Germany’s military strength, Stalin signed trade agreements supplying Germany with raw materials, including oil and grain.

These shipments supported the German war effort and strengthened the Nazi war machine in exchange for temporary security.

Due to intelligence reports warning of a German buildup, Stalin remained cautious, yet he underestimated the immediacy of the German threat.

These misjudgments delayed the Soviet Union’s full readiness for war, leaving critical vulnerabilities along the frontier. 

In June 1941, Germany suddenly launched Operation Barbarossa, shattering the non-aggression pact in a decisive and brutal betrayal.

German forces surged across the Soviet border, employing a rapid, concentrated attack known as Blitzkrieg, or ‘lightning war’.

This invasion was the largest in history, as it involved over three million German soldiers, supported by thousands of tanks, aircraft, and artillery units.

The initial assault overwhelmed Soviet defenses, capturing vast stretches of territory within weeks.

Key cities, including Minsk and Smolensk, fell quickly under the relentless German advance.

Soviet soldiers were caught unprepared. They faced staggering losses, and entire divisions were encircled and destroyed.

As a consequence, Stalin ordered a nationwide mobilization, rallying the Soviet population to resist the invasion at all costs. 

The German invasion plunged the Soviet Union into a desperate struggle for survival.

Hitler’s decision to break the pact unleashed the brutal Eastern Front, where both sides fought a merciless and devastating war.

Ultimately, Operation Barbarossa saw the collapse of any diplomatic understanding between Germany and the Soviet Union.

The Molotov–Ribbentrop Pact, once a pragmatic alliance, lay in ruins, its end signaling a new and brutal chapter in World War II.

As a result, the Eastern Front became the deadliest theater of the war.