The outbreak of the European war in 1939 marked the failure of appeasement and diplomatic negotiations, triggering a devastating conflict that reshaped global politics.
The Nazi-Soviet Pact (1939)
Motives Behind the Pact
In August 1939, Nazi Germany and the Soviet Union shocked the world by signing the Molotov-Ribbentrop Pact, formally known as the Nazi-Soviet Non-Aggression Pact. Both powers had pragmatic reasons for this unlikely agreement:
Germany’s motives:
Hitler aimed to secure Germany’s eastern frontier before invading Poland, avoiding a two-front war.
A pact with the USSR would deter Britain and France from challenging German aggression in Eastern Europe.
Economic gains: access to vital Soviet raw materials like oil, grain, and metals, crucial for sustaining Germany’s war machine.
Soviet motives:
Stalin distrusted Britain and France, having been excluded from key Western negotiations and suspecting they might push Hitler eastwards.
The USSR needed time to rebuild its military strength after Stalin’s brutal purges of the Red Army officer corps.
The pact would allow the Soviets to regain territory lost after World War I, especially in Poland and the Baltic States.
Terms of the Pact
The pact had two parts:
Public Non-Aggression Agreement:
Both Germany and the Soviet Union agreed not to attack each other or support any third party that might do so.
The pact was to last for ten years, with the possibility of extension.
Secret Protocol:
A clandestine addendum divided Eastern Europe into spheres of influence:
Poland would be partitioned roughly along the Narew, Vistula, and San rivers: western Poland to Germany, eastern Poland to the USSR.
The Baltic States (Estonia, Latvia, and later Lithuania) fell under Soviet influence.
Finland and Bessarabia (then Romanian territory) were acknowledged as Soviet interests.
Consequences of the Pact
The pact’s immediate and longer-term consequences were profound:
Facilitated German invasion of Poland by eliminating the threat of Soviet resistance.
Undermined Britain and France’s diplomatic position, revealing their failure to secure Soviet cooperation.
Gave the USSR an opportunity to expand westward without fear of German interference.
Deepened global mistrust, as the two ideological enemies colluded to redraw Eastern Europe.
When Germany invaded the USSR in June 1941 (Operation Barbarossa), the pact was exposed as a cynical temporary arrangement.
The Polish Crisis
Danzig and German Demands
After securing the Nazi-Soviet Pact, Hitler focused on Poland:
Danzig (Gdańsk), a free city under League of Nations protection but with a majority German population, became Hitler’s pretext for aggression.
Hitler demanded:
The return of Danzig to Germany.
Construction of an extraterritorial motorway and railway through the Polish Corridor, connecting mainland Germany with East Prussia.
These demands threatened Polish sovereignty and were seen as unacceptable by Warsaw.
British and French Guarantees
Poland had long resisted German territorial revisionism. When Hitler’s demands escalated in early 1939, Britain and France took a firm stand:
March 1939: Britain guaranteed Poland’s independence, with France reaffirming its alliance.
This guarantee aimed to deter German aggression and signal the end of appeasement.
Britain also strengthened ties with other Eastern European states like Romania and Greece, forming a loose anti-German front.
Despite this, neither Britain nor France could provide immediate military support to Poland due to distance and lack of preparedness.
The Outbreak of War
German Invasion of Poland
On 1 September 1939, Germany invaded Poland from the west:
The attack was swift and brutal, utilising Blitzkrieg tactics — rapid advances by tanks, motorised infantry, and coordinated air strikes.
The Polish military, though sizeable, was poorly equipped compared to the modern German Wehrmacht.
Within weeks, Poland’s defensive lines crumbled under superior German firepower.
On 17 September 1939, in line with the secret protocol, the Soviet Union invaded Poland from the east:
This two-pronged assault overwhelmed Polish forces.
By early October, Poland had ceased to exist as an independent nation, its territory divided between Germany and the USSR.
British and French Declaration of War
The German invasion crossed the final line for Britain and France:
On 3 September 1939, Britain declared war on Germany, honouring its guarantee to Poland.
France declared war shortly after, fulfilling its alliance obligations.
However, neither country launched significant immediate military operations on Germany’s western border — the so-called Phoney War began, with minimal fighting in Western Europe for several months.
Limited Immediate Support
Despite their declarations, Britain and France could not provide substantial aid to Poland:
The French army made only a minor advance into the Saar region but soon withdrew.
The Royal Air Force dropped propaganda leaflets over Germany but did not mount large bombing raids initially.
This lack of immediate military pressure on Germany allowed Hitler to focus fully on defeating Poland and preparing for Western campaigns.
Italy’s Response
Italy’s Position in 1939
Italy, under Benito Mussolini, was nominally an Axis ally of Germany but was unprepared for a major European war in 1939:
Mussolini had ambitions of expanding Italian influence but Italy’s economy and military were not ready for large-scale conflict.
Italy had just engaged in costly ventures in Ethiopia (1935–36) and the Spanish Civil War (1936–39), depleting resources.
Reasons for Delaying Entry
Mussolini chose not to join the war immediately for several reasons:
Military unpreparedness: Italy lacked modern equipment, sufficient armaments, and trained personnel for a full-scale European war.
Economic weakness: Italy’s economy could not sustain a prolonged conflict without significant German aid.
Strategic caution: Mussolini hoped to benefit from the conflict by remaining a “non-belligerent” initially, entering only when victory seemed assured and Italy could gain maximum advantage.
In private communications with Hitler, Mussolini admitted Italy would not be ready before 1943. Hitler accepted Italy’s delay, understanding Mussolini’s precarious position.
Italy’s Entry into the War
Italy finally joined the conflict in June 1940, after Germany’s stunning victories in Western Europe convinced Mussolini that the war would soon be won and Italy could share in the spoils.
Key Points
The Nazi-Soviet Pact was a pivotal factor in enabling Hitler’s invasion of Poland by neutralising the USSR as a threat and ensuring access to resources.
The Polish crisis centred on German demands for Danzig and transit rights, which Poland resisted, prompting Britain and France to issue security guarantees.
The invasion of Poland by both Germany and the USSR rapidly overwhelmed Polish defences and demonstrated the effectiveness of Blitzkrieg warfare.
Britain and France honoured their commitment to Poland by declaring war but provided little practical assistance during the crucial early weeks.
Italy’s delay in joining the war highlights the gap between fascist rhetoric and practical military readiness, as well as Mussolini’s opportunistic foreign policy.
These developments mark the failure of diplomatic containment of Germany and the decisive collapse of European peace, leading to the full-scale eruption of the Second World War.
FAQ
The British public’s reaction to the declaration of war was a complex mix of resignation, fear, and determination. Many people remembered the horrors of the First World War and had supported appeasement in the 1930s to avoid another conflict. However, by 1939, Hitler’s actions, particularly the occupation of Czechoslovakia and the invasion of Poland, convinced the public that war was unavoidable. When Neville Chamberlain announced on 3 September 1939 that Britain was at war with Germany, there was no jubilant rush to enlist as in 1914; instead, a sombre mood prevailed. The government immediately implemented air raid precautions, blackouts, and the evacuation of children from major cities to the countryside. People braced themselves for bombing raids that many expected would begin immediately. Although the feared “knockout blow” from the air did not come right away, the public remained vigilant and supportive of the war effort, recognising that confronting Hitler was necessary to defend national security and honour.
Propaganda played a significant role in shaping public opinion and maintaining morale as Britain and France edged closer to war in 1939. In Britain, government propaganda emphasised the threat posed by Nazi Germany and highlighted the need to defend freedom and democracy. Newsreels, radio broadcasts, and newspapers depicted Hitler as a ruthless dictator determined to dominate Europe. The British government also revived memories of German atrocities during the First World War to remind citizens of the consequences of unchecked aggression. Posters and leaflets encouraged people to follow blackout regulations, join the civil defence services, and accept the necessity of rationing and evacuation. In France, propaganda was less pervasive but still present, with politicians and newspapers calling for national unity in the face of German threats. However, the French population remained scarred by the heavy losses of the First World War, creating a sense of fatalism. Overall, propaganda successfully rallied people to accept the declaration of war as unavoidable and morally justified, ensuring public support for the initial mobilisation and defensive measures.
Poland chose to resist German demands and rely on Britain and France rather than negotiate for several reasons rooted in national pride, history, and geopolitics. Firstly, Poland had regained its independence only in 1918 after over a century of partitions by Russia, Prussia, and Austria, and Polish leaders were determined not to lose sovereignty again. The government viewed Hitler’s demands for Danzig and a corridor as a clear threat to its territorial integrity and political independence, fearing that accepting them would invite further demands. Secondly, Poland distrusted Germany deeply due to its aggressive policies and the clear ambitions for Lebensraum in Eastern Europe. By 1939, the rapid German rearmament and Hitler’s record of breaking agreements, such as the Munich Pact, convinced Poland that negotiation would be futile. Thirdly, Britain and France’s security guarantees in March 1939 gave Poland hope that the Western powers would deter Germany or, if necessary, provide military support. Although this hope proved misplaced militarily, it reflected Poland’s commitment to resisting German domination and upholding national sovereignty.
Other Eastern European countries reacted cautiously to the outbreak of war, balancing fear of German power against concerns about Soviet ambitions. Romania, for example, maintained formal neutrality but was wary of both Germany and the USSR due to territorial vulnerabilities like Bessarabia. Hungary, which had its own revisionist ambitions, leaned towards Germany diplomatically but did not join the conflict immediately. The Baltic States — Estonia, Latvia, and Lithuania — were caught in a dangerous position due to the secret protocols of the Nazi-Soviet Pact, which placed them in the Soviet sphere. Their governments initially tried to maintain neutrality but were soon pressured into accepting Soviet military bases and, by 1940, full Soviet occupation. Finland, though not immediately involved, would resist Soviet demands later in the Winter War of 1939–40. Overall, smaller states in the region sought to avoid provocation while quietly bracing for the possibility of German or Soviet encroachment, aware that their security depended on the balance of power between the two great dictatorships.
The invasion of Poland provided the first major demonstration of Germany’s Blitzkrieg tactics, showcasing a new style of warfare that shocked the world. Blitzkrieg, or “lightning war,” relied on speed, surprise, and close coordination between fast-moving ground forces and air support. In Poland, the German Wehrmacht used armoured divisions (Panzer units) to break through defensive lines rapidly and encircle Polish troops, cutting off their supplies and lines of retreat. Meanwhile, the Luftwaffe bombed railways, communication centres, and cities to sow confusion and disrupt mobilisation. Traditional Polish cavalry and infantry were unable to withstand such mechanised assaults, despite pockets of fierce resistance. The rapid fall of major cities like Warsaw highlighted how Blitzkrieg bypassed static defences, rendering conventional trench warfare obsolete. Although the Polish terrain and weather limited mobility at times, the operation proved the concept’s potential. This success encouraged Hitler and the German High Command to refine and use Blitzkrieg on a larger scale in Western Europe in 1940, achieving stunning victories against France and the Low Countries.
Practice Questions
Assess the significance of the Nazi-Soviet Pact in causing the outbreak of the European war in 1939.
The Nazi-Soviet Pact was highly significant in triggering the European war, as it removed Hitler’s fear of Soviet resistance, enabling the invasion of Poland without a two-front conflict. By secretly agreeing to divide Eastern Europe, Hitler and Stalin destabilised the region and undermined Britain and France’s deterrence. The pact exposed Western diplomatic failures, left Poland vulnerable, and forced Britain and France to act on their guarantees. Without this agreement, Germany might have hesitated to invade Poland, fearing Soviet opposition. Therefore, the pact directly facilitated aggression and ensured the European war would erupt in September 1939.
Explain why Britain and France declared war on Germany following the invasion of Poland.
Britain and France declared war because the German invasion of Poland blatantly violated the guarantees given to uphold Polish sovereignty. After appeasement failed with Czechoslovakia, both nations recognised that further concessions would only embolden Hitler. Public and political opinion demanded action to honour international commitments and contain German expansionism. Although militarily unprepared for immediate large-scale operations, both powers understood that credibility and security depended on resisting further Nazi aggression. The invasion demonstrated Hitler’s disregard for diplomacy, leaving Britain and France with no option but to fulfil their pledges and declare war on 3 September 1939.
