When the First World War began in August 1914, none of the 48 autonomous states that then made up the United States of America (USA) supported the taking of sides with either the Entente Powers (Britain, France and Russia) nor the Central Powers (Germany and Austria-Hungary). The USA had a professional regular army of 100,000, nearly half of which served overseas. There was also a small National Guard (a state based militia) of around 30,000.

The USA had no foreign alliances, and the President (Woodrow Wilson) made his country's position abundantly clear when, on the 19th August 1914, he made his 'Declaration of strict neutrality'. The multinational nature of the population, with large numbers of people of European stock from all the belligerent countries, probably made any other course politically impossible at that time.

Soon, the demands of the belligerent nations for food, munitions, and all kinds of strategically important materials, created a boom in the industrial and farming sectors of the American economy: a huge flow of cash and securities poured into American coffers. In particular, the eastern states of the USA benefited from this bonanza. In the 5 months of 1914 nearly 1 billion US$ of American trade goods were purchased by the Entente Powers - or the Allies as they became known after September 1914. By the end of the war it had risen to over US$ 10 billion. An astronomical sum for the time.

Simultaneously, huge multi-million dollar loans were made to the Allies by prominent eastern bankers to pay for all these goods. Early on in the war, loans were also given to the Central Powers, but on a very much smaller scale.

The severe curtailment of the global activities of the Allied and Central Powers' merchant navy fleets, also opened up unparalleled trading opportunities. These openings were readily exploited by the American traders, particularly in South America and Canada. The USA was making hay whilst the sun shone. Most of its people saw no reason to join in what they saw as the European madness.

America reacts to the German threat

Nevertheless, there was strong pressure on President Wilson by some parts of the general public, and senior cadres of the military, to increase the armed forces and for the country to be more actively involved in international politics. This tendency was greatly encouraged by what were seen as German callousness and militaristic belligerence, as exemplified by its treatment of the Belgians, its interference in Mexico and Latin America and even cases of sabotage of the Allies' industrial interests in the USA.

All these aggravations were as nothing as compared with the reaction of the American public to the increasing use by the German Navy of unrestricted submarine warfare. Even the normally quiescent Western States of the USA were stirred to protest by this flagrant disregard of the Rules of the Sea. In September 1915, prompted by these protests, President Wilson proposed a state of 'Limited Preparedness'. Shortly afterwards, the 'National Defense Act' was passed by Congress It gave gave authority for the expansion, if somewhat limited, of the Regular Army to 140,000 men, plus an increase of the National Guard reserve to 400,000. Potentially, all these troops could be required to serve overseas. The USA was tentatively girding its loins for war.

Indeed, it was the dramatic effects of the German submarine warfare, and subversive activity, which finally began the retreat of much of the USA population, and the President, from the idea of neutrality. First came the sinking of the 'Lusitania' off the coast of Ireland in May 1915, followed by the 'Sussex' in April 1916, both with the loss of many American lives.

The die is cast

The catalyst, which finally led to the involvement of the USA in the war, came, paradoxically, with the Presidential Elections of 1916 that hinged heavily on the question of neutrality. The German Navy had ceased unlimited submarine warfare after the 'Sussex' incident and this helped Wilson to stand for election on a 'Keep us out of the war' ticket. On this basis, Wilson narrowly won the election. However, despite his publicly stated policy of staying out of the war, there were clear indications that, in private, he and his advisers were already leaning towards active participation in the war in some form or another.

In this vein, on the 18th December 1916, the newly re-elected President began a round of diplomacy based on his 'Peace Note' to all the belligerent nations. It asked for clarification of their war aims to facilitate discussions, through him, on a cease-fire. However, the resulting German 'Peace Offer' was rejected by the Allies, as it was virtually the same as the conditions set out in the very demanding German initiative on the 12th December 1916; a week before Wilson's.

With peace talks thus stymied, the German High Command decided on drastic action. Wishing to hasten the end of the war in terms favourable to themselves, and confident in their ability to maintain their occupation of French and Belgian territory almost indefinitely, the German High Command, proposed an immediate resumption of attacks on Allied and neutral shipping. On the 31st January 1917, with the blessing of the German Emperor, Kaiser Wilhelm II, a state of unrestricted submarine warfare was declared. The resumption included the sinking of the merchant shipping of the Neutral Countries if they entered what the Germans called the 'War Zone'. This decision by the German High Command clearly over-rode the wishes of the German Government, led by Chancellor Theopald von Bethman-Hollweg, who, above all, were most anxious to find any alternative to renewed unrestricted submarine warfare.

President Wilson's position was wavering. On the 4th February 1917 the USA broke off diplomatic relations with Germany: a position which was more generally supported by the American public when the British Government leaked the contents of the infamous Zimmerman telegram. In this telegram, the German foreign minister was seen to be proposing the fomenting of discontent in Mexico, with the aim of encouraging it to join Germany in an alliance against the USA.

The principal objective of the Germano-Mexican Alliance would be to support Mexico in the recovery of lost territory (Arizona, New Mexico and Texas, no less!) annexed by the USA in the late 19th Century, and thus preoccupy the Americans with matters closer to home. It also indicated that Japan would be encouraged to join the Alliance.

America declares war on Germany

President Wilson's first act in the raising of the ante in the movement towards war, was to ask the US Congress for funds to combat the U-boat threat. This was granted. On the 2nd April 1917, Wilson then sought permission to go to war on the side of the Allies.

However, it was decided that there was to be no formal alliance with the Allies; the participation of the USA was to be as 'An Associated Power'. On this basis, war was declared on the German State on the 6th April 1917, followed by Austria-Hungary on the next day.

Despite active and passive dissent by various organisations and individuals, legislation was passed (The Selective Service Law) on 18th May 1917, enabling the mass conscription of American males, between the ages of 21 and 30: over 20 million men became liable for registration. The President immediately asked Congress to approve the creation of a new National Army from this huge pool of potential conscripts.

The preparations for war

With very little prior preparation, this onerous task was thrust upon the American military and naval commanders who were required to induct, and train, these conscripts for armed service.

American industry was also put on a war footing, with centralised planning. This engendered a huge expansion of production, not only for the American forces, but also those of all the Allies. Of particular importance was the highly successful shipbuilding programme; essential to convey the men and material across the Atlantic to the Western Front in Europe.

The American Expeditionary Force, (AEF)

Once a credible force had been assembled by the USA as the American Expeditionary Force (AEF), the task of taking it to Europe, and integrating it with the armed forces of the Allies, was given, in May 1917, to General John Pershing.

Pershing was a well-known American soldier with considerable experience of command in war (Cuba, Mexico and the Philippines) and colonial duties in America's overseas territories.

The 1st Division of the AEF arrived in Europe in the autumn of 1917, but spent many months in training and organisation whilst the war raged on. By May 1918, the number of the AEF's men in the field rose to half a million.

Pershing had received strict instructions from both the President, and the American Secretary of War, not to use his soldiers* until they were ready for combat, and then only under his direct command. This caused much frustration among the Allied commanders, who would have liked to absorb the Americans into their depleted ranks, in both a training and operational capacity. A measure which would have perhaps greatly reduced the heavy casualties that the battle-inexperienced AEF ultimately suffered in their own self-inflicted learning curve.

*N.B.: The American soldiers acquired various nicknames with interesting antecedents. The Americans press and general public, and many of the soldiers themselves, used the name 'Doughboys' (after a kind of American dough dumpling). The Allies called them 'Sammy's' (after Uncle Sam) or 'Yanks' (after the Yankee northern soldiers of the American Civil War). Some American soldiers also preferred 'Yanks'. By the end of the war the nickname most in use by all sides was 'Yanks'. This had eventually become acceptable to the sensibilities of all of the parties; American and the Allies. The nickname 'Yanks' was again used in Europe in the Second World War.

Pershing did finally relent from this strict control of his troops when the Germans launched their Kaiserschlacht (Plan Michael) Spring Offensive in March 1918, and the British and French were seen to be in serious trouble. Pershing seconded troops to the French embroiled in the Aisne and the Marne offensives in May/June - notably at Chateau Thierry and Belleau Wood - to the Australians at Hamel, on the Somme, and to several joint Anglo-French operations.

The AEF goes into action

It was not until the 12th September 1918, that the AEF's First US Army of half a million men, with the support of French colonial troops, planned and launched its own offensive at the St. Mihiel Salient, south of Verdun. Despite suffering enormous casualties, the Americans achieved some success, completely eliminating the salient by the 15th September, when most of the troops were withdrawn for use in the Meuse-Argonne Offensive. A second offensive, at St. Mihiel, by the AEF's Second Army, began on 10th November 1918.

The joint Franco-American Meuse-Argonne Offensive was the last major operation by the AEF. It began on the 26th September 1918 and included a breakthrough on the Kriemhilde Stellung Sector of the highly fortified Hindenburg Line. Fighting continued behind the Hindenburg Line until the Armistice in November 1918.

At the Armistice the US Army comprised of nine Corps in three Armies, with two million troops in the field and over three million more in transit or training. An even greater number was registered awaiting mobilisation.

There is little doubt that it was this potential, and actual, rapid influx of large numbers of fresh, fit men from the USA which stampeded the Germans into making the serious error of throwing their major reserves into the Spring Offensive of 1918 (Plan Michael). It also contributed to the general demoralisation of the German Army when Plan Michael failed in mid-1918, despite the German Army's early fantastic successes.

The human cost

The AEF suffered 310,708 casualties, of whom 53,513 were killed and 204,002 were wounded in action. Another 63,195 died of disease, or other non-combat causes.

In the 1918 Influenza (Spanish Flu) Epidemic, which struck the Allies and the Central Powers alike on the Western Front in the summer of 1918, many American soldiers contracted the disease; it seemed to be at its most severe in the age group of the younger serving soldier. By October 1918, over 20,000 soldiers of the AEF had died in France. Many more died in the training and transit camps in the United States.


After the Armistice, the majority of the survivors of the two million American troops that had crossed the Atlantic were gradually repatriated to the United States for demobilisation. By the 1st September 1919 only a small number remained in France. These men were occupied in the recovery and concentration of their dead comrades into US war cemeteries. Another 60,000 were based at Coblenz in Germany as part of the of the Allied Occupation Force.


The author much appreciates the observations made by David Homsher who was kind enough to point out some textual errors and incorrect data that was quoted in the original article. Mr Homsher also indicated some authorative military references on the American Expeditionary Force of the Great War that were formerly unknown to the author.