The USA and its Entry to the First World War

What did the USA do when it joined the First World War?

When the USA joined the First World War it reinforced the Allies in Europe, and helped by continuing to supply other allies with food, arms, money, and raw materials.

When did the USA join the First World War?

The USA formally declared war in April 1917.

Why did the USA enter the First World War?

The USA joined the First World War for two key reasons:

• ❖ The 'Zimmerman Telegram', from the German foreign secretary to the German ambassador in Mexico, was leaked in January 1917. It offered military and financial support if Mexico agreed to invade the USA. While the Mexicans did not agree, this created tension between Germany and the USA.
• ❖ Germany had restarted its unrestricted U-boat campaign. This resulted in the sinking of five American ships in March 1917. As the USA had warned Germany against this after the sinking of the Lusitania, it felt it had no choice but to declare war on Germany.

When did American troops arrive in Europe after they entered the First World War?

The first American troops landed in Europe in June 1917.

How did America's entry into the First World War help the Allies?

America's entry into the First World War helped in 4 key ways:

• ❖ By May 1918 there were over one million US troops in France with tens of thousands arriving each week.
• ❖ They enlarged French ports so arriving ships could deliver more men and supplies.
• ❖ They built over 1,600km of railway lines to help continue the supply chain.
• ❖ They laid over 16,000km of telephone and telegraph cables, to help improve communications between lines.

Why was US entry into the First World War important?

There were a number of significant events in which the USA was involved:

• ❖ In the Second Battle of the Marne, two divisions of American soldiers helped to prevent German forces taking Paris during the Ludendorff Offensive.
• ❖ In the Second Battle of Albert, in August 1918, 108,000 US soldiers helped capture 8,000 German soldiers.
• ❖ On 12th September 1918, in the Saint-Mihiel Offensive, 500,000 US soldiers attacked the salient created during the Ludendorff Offensive. Within four days, the salient was under Allied control.
• ❖ Between 26th September and 11th November 1918, the US led a combined US-Franco force of more than one million men. Using 300 tanks and 500 US aircraft, the force advanced 32km towards the German border.
• ❖ The US was able to supply the Allies with large numbers of tanks and artillery.