Key facts and dates

The final crisis of August-September 1939 marked the collapse of peace efforts in Europe and the outbreak of World War II. This timeline captures the pivotal events that escalated tensions and led to global conflict, highlighting the rapid sequence of diplomatic shocks and military actions.

Timeline of key events

• 23 August 1939 – Nazi-Soviet Pact announced, stunning Europe and undermining peace negotiations.
• 25 August 1939 – Anglo-Polish alliance formalised, strengthening Britain's commitment to Poland.
• Late August 1939 – Anglo-French negotiations and Italian mediation attempts fail to deter Hitler.
• 1 September 1939 – Germany invades Poland using staged provocations, without a formal declaration of war.
• 3 September 1939 – Britain declares war at 11 am, followed by France later that day.

The Nazi-Soviet Pact and its impact on peace efforts

In late August 1939, Europe was shaken by the unexpected announcement of the Nazi-Soviet Pact, a non-aggression agreement between Germany and the Soviet Union. This dramatic shift in alliances altered the diplomatic landscape and dealt a severe blow to efforts aimed at preventing war.

Key features of the Nazi-Soviet Pact

• Surprising alliance - Signed on 23 August 1939, this agreement between two ideologically opposed regimes - Nazi Germany and the communist Soviet Union - shocked the world, as few anticipated such cooperation.
• Terms of the pact - Officially a non-aggression treaty, it included secret protocols dividing Eastern Europe into spheres of influence, with Poland split between the two powers.
• Impact on peace efforts - The pact undermined Anglo-French attempts to build a united front with the Soviet Union against Germany, leaving Poland more vulnerable and weakening the credibility of deterrence strategies.

This unexpected alignment suggested that Hitler felt confident to act aggressively, believing that the Western powers were now less likely to intervene effectively.

Last-minute diplomatic attempts to avoid conflict

As tensions soared in late August 1939, Britain, France, and other parties made frantic efforts to avert war. Despite the shadow cast by the Nazi-Soviet Pact, these diplomatic moves reflected a desperate hope for a peaceful resolution.

Efforts to preserve peace

• Anglo-French negotiations - Both nations sought to deter Germany through warnings and reaffirmed their guarantees to Poland, formalising the Anglo-Polish alliance on 25 August 1939 to signal their commitment.
• Italian mediation proposals - Mussolini, wary of being dragged into a full-scale conflict, proposed last-minute peace conferences, hoping to broker a deal that might delay or prevent war, though these efforts lacked traction with Hitler.
• Warnings to Hitler - Britain and France issued direct cautions to Germany, indicating that an attack on Poland would trigger military consequences, while simultaneously mobilising their forces to underscore the seriousness of their stance.

Despite these actions, the momentum towards war seemed unstoppable, as Hitler remained unconvinced of the Western powers' resolve to fight.

Hitler's miscalculations and the invasion of Poland

Hitler's decisions during this crisis were driven by a series of misjudgements about how other nations would react to his aggression. His belief that he could act without facing significant opposition led directly to the invasion of Poland.

Factors behind Hitler's actions

• Underestimation of Western resolve - Hitler believed Britain and France would not fight, influenced by their inaction during the Munich Agreement of 1938, their earlier failures to counter German expansion, and their limited ability to provide direct military aid to Poland.
• Staged provocations - To justify aggression, German forces orchestrated fake attacks on their own border posts, blaming Polish forces as a pretext for military action.
• Invasion of Poland - On 1 September 1939, Germany launched a full-scale invasion without a formal declaration of war, employing blitzkrieg tactics to overrun Polish defences swiftly.

This act of aggression shattered any remaining hopes for peace and forced the Western powers to confront the reality of their commitments.

Britain and France's response and declarations of war

Faced with Germany's invasion of Poland, Britain and France grappled with their earlier guarantees to protect Polish sovereignty. The decision to declare war was not taken lightly, reflecting both a desire to avoid conflict and a sense of duty.

The path to declarations of war

• Internal dilemmas - Both nations agonised over their promises to Poland, torn between a strong desire to avoid another devastating war and the hope for a last-minute negotiated settlement with Hitler.
• British ultimatum - On 3 September 1939, Britain issued an ultimatum to Germany, demanding withdrawal from Poland by 11 am; when unmet, Prime Minister Neville Chamberlain announced the state of war in a sombre radio broadcast.
• French declaration - France followed suit later that day, also declaring war on Germany, honour-bound by their alliance commitments despite limited readiness for immediate action.

Polish expectations and the Phoney War

• Polish expectations - Poland anticipated a rapid Western offensive to relieve pressure from the German invasion, expecting direct military support as per the guarantees.
• Reality of the Phoney War - Instead, the period following the declarations became known as the Phoney War, where no significant military assistance was provided to Poland, leaving it to face German forces largely alone.

The significance of the crisis and the start of World War II

The events of August and September 1939 marked the definitive failure of appeasement and deterrence strategies, ushering in a global conflict. The outbreak of World War II raised critical questions about the policies and decisions that led to this point.

Key consequences and reflections

• Failure of guarantees - While the Anglo-French guarantees to Poland failed to prevent war, they determined the initial lineup of belligerents, drawing Britain and France into conflict with Germany.
• Hitler's miscalculation - Hitler's belief that the Western powers would not fight proved disastrously wrong, underestimating their resolve to uphold their commitments and marking a turning point in his aggressive expansion.
• Start of World War II - The invasion of Poland and subsequent declarations of war on 3 September 1939 signalled the beginning of a conflict that would engulf much of the world, reshaping international relations.

Critical questions for analysis

• Could earlier firmness have prevented war? - Consideration of whether stronger opposition to Hitler's earlier actions, such as the remilitarisation of the Rhineland or the annexation of Austria, might have deterred his ambitions.
• Should guarantees have been given? - Debate over whether Britain and France should have made commitments to Poland without the military capacity to support them effectively in the short term.
• Was war inevitable? - Exploration of whether, given Hitler's expansionist aims and ideological drive, conflict was unavoidable by 1939, regardless of diplomatic efforts.