The USA's entry into the First World War
Why did WW1 start?
The final straw in the tensions leading up to the First World War was the assassination of Archduke Franz Ferdinand, who was the heir presumptive to the throne of Austria-Hungary on 28th June 1914.
He was assassinated by a Serbian Nationalist, so, with Germany’s support, Austria-Hungary declared war on Serbia on July 28. Within days, Germany declared war on Russia—Serbia’s ally—and invaded France via Belgium, which then caused Britain to declare war on Germany. In short, the Alliances amongst European powers triggered a web of countries declaring war on each other. Both Britain and Russia joined the war earlier than Germany had thought they would.
The war turned into trench warfare as there was no quick victory. Overall, modern weapons made a complete and easy victory impossible.
Neutral USA
The USA was isolationist and did not see any reason to become involved in the war.
The US were able to benefit from the war by taking over both German and British markets in South America and making money by setting up loans to countries involved in the conflict.
Woodrow Wilson's policy of neutrality was popular in the USA and he was re-elected based on his commitment.
However, Germany did not view the USA as neutral because…
Britain and France were able to purchase and transport more food and industrial products from the US. This was possible because Britain controlled the Atlantic shipping routes with it's large navy.
Meanwhile, American bankers were pro-Britain and denied German access to US loans.
Reasons for the USA entering the war
As a result, Germany did something drastic. German submarines sank many American merchant ships around the British Isles and those crossing the Atlantic, which prompted the American entry into the war.
Convinced that the US was supporting Britain and its allies, German submarines began attacking ships crossing the Atlantic in 1915, which threatened American trade links with Europe.
In 1915, RMS Lusitania was sunk without warning. Over 120 Americans were killed.
President Wilson sent a strong warning which could have been interpreted as a declaration of war. William Jennings Bryan, the Secretary of State, resigned as he was isolationist. He was replaced by Robert Lansing, who opposed isolationism after the Lusitania situation.
In 1916, another attack on a passenger ship, the Sussex, saw 3 Americans killed.
After the US government threatened to cut diplomatic relations, Germany promised not to attack passenger ships. This diffused the situation for a time, although unrestricted submarine warfare was resumed in February 1917.
Zimmerman Telegram
In 1917, Britain decoded a telegram that showed German intention to attack the USA after coercing Mexico into the war with a promise to help Mexico reclaim the territories they had lost in the Mexican-American war of 1848.
After Britain made the US ambassador in London aware of the telegram, President Wilson was convinced that American interests were being severely threatened.
Declaration of War
On April 6, 1917, the USA declared war on Germany, calling the declaration "an act of high principle and idealism...to make the world safe for democracy".
Although the majority of Americans supported the war, pacifists opposed the war based on philosophical grounds, while German and Irish-American communities (which held anti-British views), openly opposed the war.
Concerned about the opposition to the War, Wilson set up the Committee on Public Information (CPI) with the aim of promoting the USA's war effort.
It organised anti-German campaigns. Huge sums of money were raised by taxation.
Impact of the USA's entry on the course of the war
The US navy was able to defeat German U-Boats in the Atlantic to create a route for vital food and material supply needed in France and Britain. Additionally, over 2 million Americans crossed to France.
At this time, Germany was struggling to replace its troops, so the US effort was short and successful.
As a result of the war, the US gained access to South American and Far East markets.
Loans to Britain and the Allies were to be repaid with interest once the war had ended.