Characters of WW1 - The Man Who Brought the USA into WW1

It is often mistakenly believed that it was the German policy of unrestricted submarine warfare that brought the USA into WW1 on 6 April 1917. Some even think it was the sinking of the Lusitania, but she was sunk on 7 May 1915. Few people are aware of the influence of the very canny Captain ‘Blinker’ Hall, the British Director of Naval Intelligence.

Reginald Hall was the son of Captain William Hall, the Royal Navy’s first Director of Naval Intelligence (DNI). He was nicknamed ‘Blinker’ (but not to his face) thanks to his habit of regularly blinking, thought to be down to a need to moisten a complaint of dry eyeballs. Up until 1914, he had had a successful career at sea and commanded the battlecruiser HMS Queen Mary, but ill health forced him ashore. He was then selected to head the Admiralty’s intelligence division in October 1914.

His predecessors had recognised the Germans’ dependence on telegraphic communications with their embassies and ships overseas, and accordingly, on the first day of the war, had arranged for the German telegraph cables in the North Sea to be severed. This meant that for communications with the Americas, the Germans were completely dependent on radio High Frequency (HF) or the mail. Not only did Hall quickly recognise the need to build up the RN’s intelligence organisation, but working with Alfred Ewing, he to set up a specialist department to intercept the Germans’ HF traffic. With the help of Marconi and the GPO, listening stations were established along Britain’s east coast and the codebreaking effort was conducted in Room 40 of the Admiralty Old Building. I have fictionalised the events in my WW1 novels. Thanks to the skill of the codebreakers with the assistance derived from the capture of German codebooks, Room 40 was very successful in reading German naval and diplomatic wireless signals and telegrams (many of the latter were passed over cables controlled by Britain). Hall, also, set up a department to intercept, open and read all mail originating from or sent abroad.

In January 1917, Room 40 achieved a real coup. They intercepted a telegram from the Minister of the German Foreign Office, Arthur Zimmermann, sent to his ambassador in Mexico. With their transatlantic cable cut, the Germans gave the coded telegram to the US embassy in Berlin for transmission over the US diplomatic channels to the German embassy in Washington where it would be forwarded to Mexico. I explain how and why this was done in my WW1 novel, The Suicide Club, but the contents once decoded were electric. Zimmermann informed the ambassador of German intentions to reinstitute the policy of unrestricted submarine warfare from 1 February 1917 and the German concerns that the sinking without warning of neutral ships might persuade the US to go to war with Germany. To counter the threat, the ambassador was instructed not only to offer an alliance with Mexico, including financial and military help to invade the southern US and, moreover, to ask Mexico to persuade Japan to switch from being an ally of Britain to making trouble on the American Pacific coast.

Hall knew that he couldn’t just hand over the telegram to the Americans. Firstly, they would think it a trick to decoy them into the war and secondly, it would betray the secrets of Room 40 and the fact that the Admiralty was reading US diplomatic traffic, too. Again, I explain the solution in The Suicide Club in more detail, but briefly, knowing that the Germans’ Washington embassy would forward the message by commercial telegraph, Hall persuaded the US embassy in London that he had come by the telegram by espionage means in Mexico. The US Ambassador was persuaded to obtain a copy of the telegram from the telegram company and the involvement of the Admiralty was thereby masked. When the contents of the telegram were made known in the US, there was general outrage and eventually, President Wilson was persuaded to declare war on Germany.

Hall was rewarded with promotion to Rear Admiral for his achievements and knighted in 1918.