2. 1914-1918: The World at War 1914-1918: The World at War Part 2 of 4

3. America Joins the Allies America Joins the Allies

4. Belgium Frustrates Germany’s Schlieffen Plan Belgium resists German passage to France Belgium says. “No!

5. German Atrocities: Real and Imagined The remains of Nurse Edith Cavell are returned to Britain. English nurse working in Belgium was executed as a spy by Germany.

6. German Atrocities: Real and Imagined

7. Stories of German Atrocities in Belgium Influence American Public Opinion

8. America to the Rescue, 1914 America to the Rescue, 1914

9. The American Relief Agency Feeds Belgian Children By answering the call for Belgium relief, in 1914, Americans all but ensured that if they entered the war, it would not be on the side of Germany (World War I. CBS Video. 1965).

10. The Sinking of the Lusitania 1915

11. America & Britain React to Sinking of the Lusitania

12.  The German restriction order of 9 September 1915 stated that attacks were only allowed on ships that were definitely British, while neutral ships were to be treated under the Prize Law rules, and no attacks on passenger liners were to be permitted at all.Prize Law German Reaction to American Protests Cartoon supporting restrictions on submarine attacks

13.  Following the sinking of an unarmed French boat, the Sussex, in the English Channel in March 1916, Wilson had threatened to sever diplomatic relations with Germany, unless the German government refrained from attacking all passenger ships, and allowed the crews of enemy merchant vessels to escape from their ships prior to any attack. More Protests from America

14. The Sussex Pledge  On May 4, 1916, the German Government accepted Wilson’s terms and conditions in what came to be known as the "Sussex pledge." The Sussex

15.  By January 1917, however, the situation in Germany had changed. During a wartime conference that month, representatives from the German navy convinced the military leadership and Kaiser Wilhelm II that a resumption of unrestricted submarine warfare could help defeat Great Britain within five months. Germany Changes Policy Kaiser Wilhelm II

16.  Accordingly, on January 31, 1917, the German Ambassador to the United States, Count Johann von Bernstorff, presented U.S. Secretary of State Robert Lansing with a note declaring Germany's intention to restart unrestricted submarine warfare the following day. Unrestricted Submarine Warfare Returns Count von Bernstorff Robert Lansing

17. Cutting the Cable  Great Britain severed Germany’s On midnight of 4 Aug 1914, the English cable ship Telconia cut Germany’s transatlantic cables, severing its communication link with the rest of the world. Now all of their communication would be funneled by wireless from Berlin and then across a cable in Africa.  Saunders, Roger. The Zimmerman Telegram - England's World War I Cryptographers, Room 40. http://modern-us-history.suite101.com/article.cfm/the_zimmerman_telegram_wwi.

18. Cipher Geeks to the Rescue  The abilities of British code breakers were greatly improved when German ciphered intercepts were given to a naval engineer named Alfred Ewing whose unique hobby was constructing ciphers. He was assigned, with a small crew, to a nondescript room with #40 on the door. This rapidly expanding group of cipher geeks was to become known as Room 40 for the duration of the war.  Saunders, Roger. The Zimmerman Telegram - England's World War I Cryptographers, Room 40. http://modern-us-history.suite101.com/article.cfm/the_zimmerman_telegram_wwi.

19. Intercepted German Codes  A German naval codebook, the Signalbuch der Kaiserlichen Marine (SKM), and maps (containing coded squares) had been passed on to the Admiralty by the Russians, who had seized them from the German cruiser Magdeburg when it had run aground off the Estonian coast on 26 August 1914. Two copies of the four that the warship had been carrying were recovered; one was retained by the Russians and the other passed to the British.MagdeburgEstonian26 August1914  Room 40. http://en.wikipedia.org/wiki/Room_40.

20. German Code “Cracked”  In October, 1914 the British also obtained the Imperial German Navy's Handelsschiffsverkehrsbuch (HVB), a codebook used by German naval warships, merchantmen, naval zeppelins and U-Boats. This had been captured from the German steamer Hobart by the Royal Australian Navy on 11 October. On 30 November a British trawler recovered a safe from the sunken German destroyer S-119, in which was found the Verkehrsbuch (VB), the code used by the Germans to communicate with naval attachés, embassies and warships overseas. Imperial German NavyzeppelinsU-Boats Royal Australian Navy11 October30 November  Room 40. http://en.wikipedia.org/wiki/Room_40.

21. Room 40  In the history of cryptography, Room 40 (NID25) was the room in the Admiralty most identified with the British cryptography effort during World War I.history of cryptographyAdmiraltycryptographyWorld War I  It was formed shortly after the start of the war in October 1914. Admiral Oliver, the Director of Naval Intelligence, gave intercepts from the German radio station at Nauen near Berlin to Director of Naval Education Alfred Ewing, who constructed ciphers as a hobby. Ewing recruited civilians such as William Montgomery, a translator of theological works from German, and Nigel de Grey, a publisher.1914Alfred EwingWilliam Montgomery Nigel de Grey  Room 40. http://en.wikipedia.org/wiki/Room_40.

22.  On January 19, 1917, British naval intelligence had intercepted and decrypted a telegram sent by German Foreign Minister, Arthur Zimmermann, to the German Ambassador in Mexico City. A Secret Telegram is Sent Arthur Zimmermann

23. Secure Cable Tapped  The Zimmermann Telegram was sent through a supposedly secure transatlantic cable, belonging to Scandinavia and devoted to peace negotiations, on January 19th 1917. The Zimmermann Telegram, often called the “Zimmermann Note”, was a memo sent from the German Foreign Minister Arthur Zimmermann to the German Ambassador to Mexico. It informed the ambassador that Germany would be resuming its policy of Unrestricted Submarine Warfare (USW) and, crucially, ordered him to propose an alliance with Mexico.  The Zimmermann Telegram. http://yourarchives.nationalarchives.gov.uk/index.php?title=The_Zimmermann_Telegr am. http://yourarchives.nationalarchives.gov.uk/index.php?title=The_Zimmermann_Telegr am

24. The Zimmermann Telegram as it was forwarded to Mexico.

25. A portion of the Telegram as decrypted by the British Naval Intelligence code breakers. Zimmermann Telegram Room 40 of the British Admiralty where codes were broken during the Great War

26.  The British had initially not shared the news of the Zimmerman Telegram with U.S. officials, because they did not want the Germans to discover that British code breakers had cracked the German code.  However, following Germany's resumption of unrestricted submarine warfare in February, the British decided to use the note to help sway American official and public opinion to join the war. Britain Sends Secret Telegram to Wilson

27. Decoded Telegram

28. Telegram Sent to the German Ambassador in Mexico  Berlin, January 19, 1917  On the first of February we intend to begin submarine warfare unrestricted. In spite of this, it is our intention to endeavor to keep neutral the United States of America.  If this attempt is not successful, we propose an alliance on the following basis with Mexico: That we shall make war together and together make peace. We shall give general financial support, and it is understood that Mexico is to reconquer the lost territory in New Mexico, Texas, and Arizona. The details are left to you for settlement....  You are instructed to inform the President of Mexico of the above in the greatest confidence as soon as it is certain that there will be an outbreak of war with the United States and suggest that the President of Mexico, on his own initiative, should communicate with Japan suggesting adherence at once to this plan; at the same time, offer to mediate between Germany and Japan.  Please call to the attention of the President of Mexico that the employment of ruthless submarine warfare now promises to compel England to make peace in a few months.  Zimmermann (Secretary of State)

29. Map showing Mexican territory in 1917 (dark green), with territoryMexican promised to Mexico in the Zimmermann telegram denoted in light green. Land Promised to Mexico

30. Was Germany serious about its promises to Mexico?

31.  The British finally forwarded the intercepted telegram to Wilson on February 24. The American press carried the story the following week.  However, by 1917, the continued submarine attacks on American merchant and passenger ships, and the "Zimmermann Telegram's" implied threat of a German attack on the United States, had served to sway American public opinion in support of a declaration of war. America Supports War with German

32. The Time to Act is Wilson convenes Congress two weeks early to seek war declaration approval. Now!

33. America Declares War, 1917