Washington Naval Treaty

Washington Naval Treaty
Limitation of Naval Armament
Washington Naval Treaty.jpg
Signing of the Washington Naval Treaty.
TypeArms control
ContextWorld War I
SignedFebruary 6, 1922 (1922-02-06)
LocationMemorial Continental Hall, Washington, D.C.
EffectiveAugust 17, 1923 (1923-08-17)
ExpirationDecember 31, 1936 (1936-12-31)
Washington Naval Treaty, 1922 at Wikisource

The Washington Naval Treaty, also known as the Five-Power Treaty, the Four-Power Treaty, and the Nine-Power Treaty, was a treaty signed during 1922 among the major nations that had won World War I, which agreed to prevent an arms race by limiting naval construction. It was negotiated at the Washington Naval Conference, held in Washington, D.C., from November 1921 to February 1922, and it was signed by the governments of the United Kingdom, the United States, France, Italy, and Japan. It limited the construction of battleships, battlecruisers and aircraft carriers by the signatories. The numbers of other categories of warships, including cruisers, destroyers and submarines, were not limited by the treaty, but those ships were limited to 10,000 tons displacement each.

The treaty was concluded on February 6, 1922. Ratifications of that treaty were exchanged in Washington on August 17, 1923, and it was registered in the League of Nations Treaty Series on April 16, 1924.[1]

Later naval arms limitation conferences sought additional limitations of warship building. The terms of the Washington treaty were modified by the London Naval Treaty of 1930 and the Second London Naval Treaty of 1936. By the mid-1930s, Japan and Italy renounced the treaties while Germany had renounced the Treaty of Versailles (Germany, which was not a party to the Washington Naval Treaty, had already had its navy limited in size by the Treaty of Versailles), making naval arms limitation increasingly difficult for the other signatories.


Immediately after World War I, the United Kingdom had the world's largest and most powerful navy, followed by the United States and more distantly by Japan, France and Italy. The High Seas Fleet of defeated Germany had been interned by the British. The allies had differing opinions concerning the final disposition of the German fleet, with the French and Italians wanting the German fleet divided between the victorious powers and the Americans and British wanting the ships destroyed. These negotiations became mostly moot when the German crews scuttled most of their ships. News of the scuttling angered the French and Italians, with the French particularly unimpressed with British explanations that their fleet guarding the Germans had been away on exercises at the time. Nevertheless, the British joined their allies in condemning the German actions and no credible evidence emerged to suggest that the British had collaborated actively with the Germans with respect to the scuttling. The Treaty of Versailles, signed soon after the scuttling of the German High Seas Fleet, imposed strict limits on the size and number of warships that the newly-installed German government was allowed to build and maintain.

The US, UK, France, Italy, and Japan had been allied for World War I; but with the German threat seemingly finished, a naval arms race between the erstwhile allies seemed likely for the next few years.[2] President Woodrow Wilson's administration had already announced successive plans for the expansion of the US Navy from 1916 to 1919 that would have resulted in a massive fleet of 50 modern battleships.[3]

In response, the Japanese parliament finally authorized construction of warships to enable the Japanese Navy to attain its goal of an "eight-eight" fleet programme, with eight modern battleships and eight battlecruisers. The Japanese started work on four battleships and four battlecruisers, all much larger and more powerful than those of the classes preceding.[4]

The 1921 British Naval Estimates planned four battleships and four battlecruisers, with another four battleships to follow the subsequent year.[2]

The new arms race was unwelcome to the U.S. public. The United States Congress disapproved of Wilson's 1919 naval expansion plan, and during the 1920 presidential election campaign, politics resumed the non-interventionalism of the prewar era, with little enthusiasm for continued naval expansion.[5] Britain also could ill afford any resumption of battleship construction, given the exorbitant cost.[6]

During late 1921, the USA government became aware that Britain was planning a conference to discuss the strategic situation in the Pacific and Far East regions. To forestall the conference and satisfy domestic demands for a global disarmament conference, the Harding administration called the Washington Naval Conference during November 1921.[7]

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