The United States remained neutral at the beginning of World War 1 and did not enter the war until 6 April, 1917. Initially, the United States supplied finances, raw materials, armaments and food to both the Allies and the Central Powers. However, a successful British blockade severely limited trade with the Central Powers. While individual Americans supported one side or the other, most agreed with President Woodrow Wilson’s policy of non-intervention.

The sinking of the RMS Lusitania is frequently referred to as the incident that drew the US into the war on the side of the Allies. The sinking occurred on 7 May 1915, almost two years before the United States entered the war. It is, however, certain that the sinking of the Lusitania changed the opinion of many Americans regarding their neutrality and increased support for the Allies. Although most of those lost in the sinking were British or Canadians, there were 128 Americans lost in the disaster.

While a German declaration of unrestricted submarine warfare is the standard answer as to why the US entered the war, there’s also the infamous Zimmerman telegram. In a secret cable to the Mexican embassy in January 1917, the secret diplomatic communication was intercepted and decoded by British intelligence. In the telegram, the German Foreign Minister, Arthur Zimmermann, proposed a military alliance between Germany, Mexico, and Japan should the United States enter the war. It basically offered the return of Texas, Arizona, and New Mexico to Mexico as spoils should the Central Powers be successful.

Disclosure of the contents of the telegram enraged Americans and helped to generate support for the American declaration of war on Germany in April.

The United States enters the War

As late as 1917, the United States was ill prepared for a war, maintaining only a small army. That changed rapidly and by the summer of 1918 about 2 million US soldiers had arrived in France, only about half of whom eventually saw front-line service. At its peak, 10,000 fresh US soldiers were arriving in France daily.  The Germans miscalculated the United States’ influence on the outcome of the conflict, believing it would be many more months before US troops would arrive and overestimating the effectiveness of U-boats in slowing the American buildup.

The arrival of the American Expeditionary Force (AEF) came at a pivotal point in the war. The Bolshevik Revolution in Russia and the formation of the Soviet Union saw the end of their hostilities with Central Powers. This released 33 battle hardened German divisions to bolster the Western Front. This meant that the 178 Allied divisions now faced 192 divisions of undoubtably one of the finest fighting machines in the world, the German Army.

When he arrived in Europe, Pershing had openly scorned the slow trench warfare of the previous three years on the Western Front, believing that American soldiers’ skill with the rifle would enable them to avoid costly and senseless fighting over a small area of no-man’s land. This was regarded as unrealistic by other Allied commanders, and (privately) by a number of his own generals. The AEF performed well in the relatively open warfare of the Second Battle of the Marne against little resistance. However, against established German defensive positions, such as in the Argonne, their performance and casualty rates were not noticeably better than that of the Allied offensive on the Somme 2 years earlier. While more ground was gained, by this stage of the war the German Army was in worse shape than previously.

The AEF saw it’s first major engagement at the Battle of Saint-Mihiel from 12–15 September 1918 as part of the Last 100 Days Offensive. In that battle, the attack caught the Germans retreating from their positions. Their artillery was out of place and the American attack, coming up against disorganized German forces, proved more successful than anticipated. However, the attack began to fall apart when the advancing infantry and tanks began to outrun their logistics and artillery support. The key objective of the battle, capturing the city of Metz , was not achieved.

Probably Pershing’s greatest folly was that he would not allow American soldiers to fight under foreign command. “I will not parcel out American boys.” This is a position that has been maintained by American commanders since then. In doing this, the Americans lost the advantage of learning from those who had learned the hard way and spent an inordinate amount of time, and lives, to get up to speed with their Allies. He would have done well to have heeded the words of a fellow American, George Santayana, who said “Those who do not know history’s mistakes are doomed to repeat them.”

A British observer from British Army Headquarters reported 400 American soldiers dying of starvation and wounded men dying because they could not get back to the casualty clearing stations because of constant transport breakdowns. These situations had devastating effect on the morale of the American soldiers.

Pershing would frequently find himself at odds with other national commanders and the the Supreme Allied Commander, French General Foch. In a letter to Foch, French Prime Minister Clemenceau referred to Pershing’s “invincible obstinancy” and that the Americans were “unusable, simply because they were unused“. In spite of their large numbers, Pershing’s intransigence would result in high casualties and while they remained rather ineffective. General Erich Ludendorff, Chief of Staff of the German Army, commented about the effectiveness of the US Army by saying “The fact that new American reinforcements could relieve British and French divisions on quiet sectors weighed heavily in the balance against us.”

The results of the AEF as compared to those of the Canadian Corps during the Last 100 Days offers an idea of the effectiveness of both fighting forces:

	American Forces	Canadian Corps
Number of troops deployed	650,000	105,000
Number of divisions deployed	26	4
Days engaged with the enemy	47	100
Advances in kilometres	54	138
Number of German divisions faced	46	47
German Prisoners captured	~16,000	31,537
German artillery pieces captured	468	623
Total Casualties	102,000	45,830

There is no question that the entry of the United States into the war on the side of the Allies impacted the outcome of the war. However, one must not lose sight of the fact that the AEF did not face the German Army at its strength. The failure of the German Spring Offensive and the collapse of the other members of the Central Powers greatly influenced the morale of the German soldier and their resolve to fight. The American claim that their entry into the war had brought victory to the Allies was met by a curt assessment by a Canadian officer that the American Army’s famed Rainbow Division was well named: Having arrived after the storm.

Honour the Fallen; Help the Living