Telegram that led US to war
It has been said that the first casualty in war is truth, and it was no more so than in March 1917 as the UK used secretly gathered intelligence to manipulate the United States towards a declaration of war on Germany.
In January 1917, British Naval Intelligence, led by Admiral ‘Blinker’ Hall’s Room 40, the predecessor of Bletchley Park, intercepted and partially decoded a secret telegram passing through the US Embassy in London to Washington, the contents of which would cause outrage in America.
The launch of unrestricted submarine warfare in February had caused a rupture in US-German relations, but prior to that Germany had been allowed the facility of using the protected diplomatic channels of the United States to send messages for onward transmission. Britain had control of all the transatlantic cables, having severed the German’s undersea cables on the outbreak of the war.
The infamous Zimmerman telegram, named after its author, the German foreign minister, was sent to the US in code, then forwarded in code to Mexico by Western Union. The telegram invited the Mexican government to join the war on the German side on the promise of recovering ‘lost’ territories in Texas, New Mexico and Arizona.
The difficulty for British intelligence was that it could not reveal that it had been secretly reading messages sent through US diplomatic channels. It would not have helped to get America into the war on our side to have to reveal that we were reading US diplomatic cables.
By a ruse, the British persuaded the US government that it ought to obtain a copy of the onward telegram sent by Western Union to Mexico. A British intelligence officer then purported to decode the telegram in the offices of US intelligence, where the Americans were astonished to read the intent of Zimmerman to persuade Mexico to attack the US, as well as to try to persuade the Mexican government to incite Japan to attack the US. Even then the US and Japan were rivals in the Pacific.
The publication of the telegram in the US press on March 1, 1917, caused outrage and was another nail in the coffin for Germany’s attempts to keep the US out of the war in Europe by engineering a war on America’s southern border and in her Pacific possessions.
By the end of the month America was on the verge of war with Germany as mounting shipping losses and US citizens being killed at sea allowed President Wilson to get congress to agree to a declaration of war.
Britain would continue to secretly monitor US diplomatic traffic for many years afterwards. Since the Second World War we have had close co-operation between the intelligence services and US agencies, and an understanding that we do not monitor the others’ communications.
The project will be holding a sale of books on a wide range of subjects on Saturday, from 10am to 4pm, at the Old Low Light Heritage Centre. Admission free.
New volunteers are welcome to join the project. To find out more contact firstname.lastname@example.org or call into the workroom at Linskill Community Centre, North Shields, which is open from 10am to 4pm each weekday for enquiries and for anyone to bring information about relatives lost in the war.