Declarations of war during World War II

Animated map of the European Theater of war during WW II

This is a timeline of formal Declarations of War during World War II.

A Declaration of War is a formal act by which one nation goes to war against another. The declaration is usually an act of delivering a performative speech (not to be confused with a mere speech) or the presentation of a signed document by an authorized party of a national government in order to create a state of war between two or more sovereign states. The official international protocol for declaring war was defined in The Hague Peace Conference of 1907 (or Hague II).[1] For the diplomatic maneuvering behind these events which led to hostilities between nations during World War II, see the article entitled Diplomatic history of World War II.

List of war declarations

Below is a table showing the Outbreaks of Wars between Nations which occurred during World War II. Indicated are the dates (during the immediate build-up to, or during the course of, World War II), from which a de facto state of war existed between nations. The table shows both the "Initiator Nation(s)" and the nation at which the aggression was aimed, or "Targeted Nation(s)". Events listed include those in which there were simple diplomatic breaking of relations that did not involve any physical attack, as well as those involving overt declarations or acts of aggression.[2]

Outbreaks of Wars between Nations during World War II
Table Legend: Concerning "Declaration of War: Type." A = Attack without prior, formal declaration of war; U = State of war arrived at through use of ultimatum;
W = Formal declaration of war made.
DateInitiator Nation(s)Targeted Nation(s)Declaration of War: TypeNotes/CommentsDocument/Event
1939-09-01 GermanyPoland A [3][4]German attack began at 4:45 am[3][5]Invasion
1939-09-03 United Kingdom, FranceGermany U [3][4]At 11 O'clock (am) British PM, Neville Chamberlain publicly delivered his Ultimatum Speech.[4][6][7]Document
1939-09-03 Australia, New ZealandGermany W[3][4]

Australia

New Zealand

1939-09-06 South AfricaGermany W[3][4] Declaration
1939-09-10 CanadaGermany W[3][4] Declaration
1939-09-17 Soviet UnionPoland A[3][4] Invasion
1939-11-30 Soviet UnionFinland A[3][4] First war between these nations.Invasion
1940-04-09 GermanyDenmark, Norway A[3] Invasion
1940-05-10 GermanyBelgium, Netherlands A/W[3][4] Date of the German offensive in the West, W from Belgium and the Netherlands.[8]

Belgium

Netherlands

1940-05-10 GermanyLuxemburg A[4] Luxembourg
1940-06-10 ItalyFrance, United Kingdom W[3][4] France and the UK
1940-06-10 CanadaItaly W[3] Declaration
1940-06-11 South Africa, Australia, New ZealandItaly W[3]

South Africa

Australia

New Zealand

1940-06-11 FranceItaly[3] Declaration
1940-10-28 ItalyGreece U[4] Italy invades Greece Invasion
1941-04-06 GermanyGreece W[3][4] Invasion
1941-04-06 Germany, BulgariaYugoslavia A[3][4] Invasion
1941-04-06 Italy, HungaryYugoslavia A[4] Invasion
1941-06-22 Germany, Italy, RomaniaSoviet Union A[3][4] A timed-declaration of war was given by Germany at the time of the attack[9]Invasion
1941-06-25 FinlandSoviet Union W Finland recognized a state of war with the Soviet Union; second war between these nations.Finnish aim: recaptue of lost territories during the first war. Possible through the German attack on USSR.
1941-06-27 HungarySoviet Union W[4] Invasion
1941-12-06 United Kingdom Finland U[4] Declaration
1941-12-07 United KingdomRomania, Hungary U[4] Declaration
1941-12-07 Empire of JapanUnited States and the British Empire A[3] W (Japanese point of view); A The "Western" (Attack on Pearl Harbor);

Declaration

Attack on Pearl Harbor

Invasion of Malaya

Attack on Singapore

Invasion of Hong Kong

1941-12-07 Canada, Australia, New Zealand Japan, Finland, Romania, Hungary W[4]

Canada

Australia

New Zealand

1941-12-07 United Kingdom Romania, Finland and Hungary W[4] Declaration
1941-12-07 Panama Japan W[4] Declaration
1941-12-08 United States, United Kingdom, Australia, Costa Rica, Dominican Republic, El Salvador, Haiti, Honduras, The Netherlands, New Zealand and Nicaragua Japan W[4]

American declaration

British declaration

Australian declaration

Cost Rican declaration

Dominican Republic's declaration

Salvadorian declaration

Haitian declaration

Honduran declaration

Dutch declaration

New Zealand's declaration

Nicaraguan declaration

1941-12-08 South AfricaJapan W[4] South African declaration
1941-12-08 ChinaGermany, Italy, Japan W[4] Declaration
1941-12-09 Australia, New ZealandJapan W[4]

Australian declaration

New Zealand's declaration

1941-12-11 Germany, ItalyUnited States W[3][4]

German declaration

Italian declaration

1941-12-11 United StatesGermany, Italy W[3] Germany

Italy

1941-12-11 Poland's government-in-exileJapan W[3]Japan rejected declaration of War. Prime Minister Hideki Tōjō's answer was following: "We don't accept the Polish declaration of war. The Poles, fighting for their freedom, declared war under the British pressure".
1941-12-12 Romania, Bulgaria United States, United Kingdom W[4]

Romanian declaration

Bulgarian declaration

1941-12-13 United Kingdom, New Zealand, South Africa Bulgaria W[4]

British declaration

New Zealand's declaration

South African declaration

1941-12-13 HungaryUnited States W[4] Declaration
1941-12-14 Croatia United States, United Kingdom W[4] Declaration
1941-12-16 Czechoslovak government-in-exile all countries at war with the United States, United Kingdom, or the Soviet Union W Declaration
1941-12-17 Albania United States W Declaration
1941-12-19 Nicaragua Bulgaria, Hungary and Romania W Declaration
1941-12-20 Belgium Japan W Declaration
1942-01-01 United Nations Axis powers W Declared during Arcadia Conference Declaration
1942-01-06 Australia Bulgaria W Declaration
1942-01-25 United Kingdom, New Zealand, South Africa Thailand W

British declaration

New Zealand's declaration

South African declaration

1942-05-22 MexicoGermany, Italy, Japan W[4] Declaration
1942-08-22 BrazilGermany, Italy W Declaration
1943-04-02 Bolivia Axis members W Declaration
1943-09-09 IranGermany W Declaration
1943-10-13 ItalyGermany W[3] Italy had changed side after the fall of Mussolini. The Declaration of War was given by Pietro Badoglio to the German ambassador in Madrid.[3] Declaration
1944-08-25 RomaniaGermany, Hungary W Romania switched sides Declaration
1944-09-05 Soviet UnionBulgaria W Declaration
1944-09-08 BulgariaGermany W Bulgaria switched sidesDeclaration
1945-02-07 Argentina, Paraguay Germany, Japan W

Argentinean declaration

Paraguayan declaration

1945-02-12 Peru Germany, Japan W Declaration
1945-02-15 Venezuela, Uruguay Germany, Japan W

Venezuelan declaration

Uruguayan declaration

1945-02-21 San Marino Germany W Declaration
1945-02-23 Turkey Germany, Japan W Declaration
1945-02-24 EgyptGermany, Japan W Declaration
1945-02-26 Syria Germany, Japan W Declaration
1945-04-01 Saudi Arabia Japan W Declaration
1945-04-03 FinlandGermany W Finland switched sides Declaration
1945-04-11 Chile Japan W Declaration
1945-07-06 BrazilJapan W Declaration
1945-07-14 ItalyJapan W Declaration
1945-08-08 Soviet UnionJapan W[3] Last outbreak of war during the entire Second World War. Declaration

Literature

References

  1. On the Opening of Hostilities; 1907; Yale Law School Library; retrieved March 2014.
  2. Note:In rare cases, war between two nations occurred twice, with an intermittent period of peace. The list here does not include peace treaties or periods of any armistices.
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 3.20 3.21 3.22 3.23 "2194 Days of War"; (1977); Salmaggi, C. & Pallasvini, A.; ISBN 91-582-0426-1; per tables included. [Italian; American]
  4. 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 4.12 4.13 4.14 4.15 4.16 4.17 4.18 4.19 4.20 4.21 4.22 4.23 4.24 4.25 4.26 4.27 4.28 4.29 4.30 4.31 Timeline Data; World at War online; retrieved February 2014.
  5. On This Day
  6. Note: Included in the speech: "...This morning, the British Ambassador in Berlin handed the German Government a final note, stating that unless we heard from them by 11 O'clock that they were prepared at once to withdraw their troops from Poland a state of war would exist between us. I have to tell you now that no such undertaking has been received and that consequently this country is at war with Germany..."
  7. 1939: Britain and France declare war on Germany, BBC
  8. Swedish Encyklopedia; "Bonniers Lexikon" (Vol. 1); (c.1960s); table in article by Andra Världskriget: The Second World War; Pp. 461-462.
  9. "The Rise and Fall of the Third Reich"; Shirer, William L