The United States of America declared War on Germany on 6th April 1917.
German unrestricted submarine warfare
America had vocally led a neutral bloc of countries in condemning Imperial Germany’s policy of unrestricted submarine warfare.
Germany had pursued a policy of unrestricted submarine warfare, whereby it attacked all shipping, in an effort to hamper Britain’s war effort, by starving it of resources.
Germany had abandoned the policy of unrestricted submarine warfare after the sinking of RMS Lusitania by German U-boats in 1915.
The sinking of RMS Lusitania resulted in the loss of many civilians, including a sizeable number of American causalities, and led to the international condemnation of Germany.
However, the prospect of the revival of the policy in 1917 fuelled American entry into the conflict.
The Zimmerman Telegram
The Zimmerman Telegram was a coded telegram passed from The Imperial Government of Germany to the Government of Mexico, deciphered by the British.
The telegram contained a proposal from the German Empire to Mexico for an offensive and defensive alliance.
The Zimmerman Telegram stated that Germany and Mexico would: “make war together, make peace together, [there would be] generous financial support [from Germany to Mexico] and an understanding on our [Germany’s] part that Mexico is to reconquer the lost territory in Texas, New Mexico, and Arizona”.
The deciphered message was passed from the British to the US Embassy in London.
The prospect of an anti-USA alliance between Germany and Mexico, along with the German policy of unrestricted submarine warfare, ultimately led to the USA’s declaration of war on Germany in 1917.
Posted by: Daniel Barry, Centenary News