WORLD WAR 1
In 1914 the United States Army comprised 98,000 men, of whom some 45,000 were stationed overseas. The Regular Army was backed up by the 27,000 troops in the National Guard. As early as December 1914 General Leonard Wood helped to form the National Security League and began arguing for conscription to increase the size of the US Army. The US President Woodrow Wilson responded to this pressure by increasing the standing army to 140,000 men.
When the USA declared war on Germany in April 1917, Wilson sent the American Expeditionary Force (AEF) under the command of General John Pershing to support the Allies in France. The largest of the battles the AEF fought in WW1 was the Battle of Meuse–Argonne from 26 Sep 1918 – 20 Oct 1918 and was was a part of the final Allied offensive of World War I that stretched along the entire Western Front. It was fought from September 26, 1918, until the Armistice on November 11, a total of 47 days.
The battle was the largest in United States military history and was the largest frontline commitment of troops by the U.S. Army in World War I, and also it's deadliest. It involved 1.2 million American soldiers of whom the AEF lost 26,277 killed and 95,786 wounded, and all this in only a 6 week period. To this day it remains the greatest loss of men in any battle that American forces have fought in.
The Meuse-Argonne Offensive was a very complex operation involving a majority of the American ground forces having to fight upwards through rough, hilly terrain that the German army had spent four years in building up their fortifications into virtually impregnable defensive positions. The battle objectives was the capture of the railroads at Sedan which would break the rail net supporting the German Army in France and Flanders and force the enemy's withdrawal from the occupied territories.
The Meuse-Argonne was the principal engagement of the American Expeditionary Forces during the First World War. It was during the offensive (October 8) that Corporal (later Sergeant) Alvin York made his famous capture of 132 German prisoners near Cornay.
In overall reckoning however with the fighting in World War I the price the AEF paid in deaths was seen as 'modest' compared to the overall losses suffered by Britain and France and the Commonwealth countries of Australia, Canada, NZ, India etc as well as Russia and Germany. The AEF final casualty rate was 116,708 men killed in action and 205,690 wounded.
However, if you take into consideration the fact that the AEF only entered into front line battle conditions in late October 1917 (and then only in limited numbers) and not until June 1918 during the second battle of the Marne that they really engaged in full scale battle - their casualty rate measured in actual time in battle was horrendous. It was also a conflict that saw the US Marine Corps in action on European soil – in World War II they would fight exclusively in the Pacific theatre.
This casualty rate information was largely eclipsed back in the USA by the global influenza pandemic during the autumn of 1918 which took the lives of more than 25,000 men from the AEF while another 360,000 became gravely ill. Other diseases were relatively well controlled through compulsory vaccination.
By the end of the war, 119 men had been awarded the Medal of Honour for supreme courage; 90 from the Army, 21 from the Navy, and eight from the US Marine Corps. Of the men awarded the Medal of Honour - for 33 it was a posthumous award. Among the recipients were Sergeant Alvin York, and the fighter ace Edward "Eddy" Rickenbacker while the first US Marine Corps pilot to win the Medal of Honour was Ralph Talbot.