In the wake of the Zimmermann Telegram and the German resumption of unrestricted submarine warfare in the Atlantic, the United States entered the First World War in April 1917. How did American intervention affect the course of the First World War?
This article is an edited transcript of America’s Entry into the First World War – Michael Neiberg, available on History Hit TV.
Listen NowGerman reaction
Germany was not particularly afraid of the Americans to begin with. The American army was very small.  And even though Mexico rejected the Zimmermann Telegram, which sought to form an alliance between Mexico and Germany, the United States still had to leave a portion of  its army back in the United States. This is perhaps one reason why Germany was prepared to take the great gamble of reintroducing unrestricted submarine warfare and the Zimmermann Telegram. They believed the risk of the United States making a difference was relatively remote. Germany was aware, however, that the American economy – American industry – would now wind up to full force.
Germany was not particularly afraid of the Americans to begin with.
America gets into gear
America’s decision to transform itself into a military power in order to participate fully in the war was driven in part by post-war considerations. President Wilson was aware that if America didn’t make a genuine contribution to victory on the ground, then the United States would struggle to enforce its beliefs at the post-war peace conference.
America fought, as Wilson said, not as an Ally but as an associated power of the Alliance. The reason he used that rhetoric was that he believed the United States was fighting for different things than the British and French. Wilson’s 14 points, when studied carefully, actually contain anti-British and anti-French sentiments. They’re anti-imperial, they’re against any kind of control over freedom of the seas. This difference means the American contribution must be distinctive.
The other driving force was the will of the American people. They didn’t want the United States to fight the war simply with navies, and with finance, and with industry. They wanted to be involved on the ground.
A workman poses next to a mountain of socks, produced for the American Expeditionary Force
Working well with others
America sent an expeditionary force to France. But this brought about complex issues around command and the role of the Americans alongside the French and British. Britain and France, being short of manpower, needed the Americans to plug gaps in their lines. But the Americans wanted to fight as a distinctive force. It would be extremely difficult for an American president to break apart units or regiments and place them under somebody else’s command. That would be incomprehensible politically in the United States..
…the Americans wanted to fight as a distinctive force
Watch NowOn the other hand, the United States had never in its history put together a force like this to fight a war like this.
To solve this issue, a compromise was reached that meant Americans would command Americans up to the division level. In American terms that means about 22,000 men. Anything above that, at least initially, would work through the British and French system. This took away the questions of how to structure a higher headquarters, how to integrate artillery, aviation, communications, all the things that American officers had never before done. They were aware they needed help. But they went to the French much more than they did to the British to work within those general staff systems.
This system worked until about mid-summer 1918, when an agreement was reached between the French, and Ferdinand Foch, and the American General John Pershing, to create a separate American sector of the Western Front.
US troops during the Meuse Argonne campaign, the largest US military campaign up to that point
A decisive factor?
Did US involvement decide the outcome of the war? On balance, probably not.  Having said that, American entry was absolutely crucial in terms of timing and the resources the US could bring to bear. American entry into the war happened just as the Russians were getting out. Without American entry, the Germans, and the Central Powers more generally, would have been able to reorient a lot more effort against the Allies. In conclusion, it’s still a coalition effort, it’s still a joint effort, it’s still an alliance effort, but the American entry into the war was absolutely crucial.
