AEF was deployed intact as a separate field army, and was ready for combat
operations by August of 1918. Some US formations fought successful tactical
actions against the Germans earlier during the Battles of Cantigny (May) and
Chateau-Thierry and Belleau Wood (June). However, it was not until the
St. Mihiel and Meuse–Argonne offensives in September 1918 that Americans
actually put their operational doctrine into practice on the battlefield. 13
The St. Mihiel offensive began on 12 September; nine US divisions and five
French divisions attacked after a four-hour artillery barrage, supported by 3,000
guns, 267 tanks, and 1,500 aircraft. 14 The attack met with little resistance as the
Germans had already begun to withdraw, leaving only outposts in the forward
lines; some 15,000 German prisoners were captured at a cost of 7,000 Allied
casualties. The Meuse–Argonne offensive began on 26 September, with fifty-two
American divisions (1,250,000 men) participating, though ten of those served in
French and British armies. The operation was supported by over 1,000 planes,
2,700 guns, and nearly 200 tanks, while the infantry enjoyed an 8:1 numerical
superiority. 15 The attack had to cross very difficult terrain in the Argonne Forest
and to penetrate three lines of German defences. Progress was painfully slow for
the first few days, but did cause the Germans to send a cable to President Wilson
requesting a peace settlement based on his Fourteen Points. However, the Allies
continued to push the offensive. By the armistice, the AEF had about 1,250,000
troops engaged in the offensive, and it suffered about 120,000 casualties of all
types (about ten per cent of its fighting strength), of whom about 25,000 were
killed; for that price, it had advanced some thirty-four miles and occupied 580
square miles of territory. 16 (American casualties overall by the time of the
armistice were about 320,710.) 17
Overall, the operations were successful. Still, the operational performance of
the AEF left quite a bit of room for improvement. It is worth pointing out,
however, that the command had only three months of experience at practising the
operational art before the armistice ended hostilities on 11 November 1918. Not
surprisingly, the lack of practical operational experience among senior comman-
ders and staffs was a significant problem. It was particularly evident in the
amount of time higher command echelons took to develop and issue orders;
they were also slow to perceive and respond to changes in the situation. They
‘fought the plan, rather than the enemy’, as the expression goes, meaning they
adhered rather too rigidly to the scheme of manoeuvre instead of exploiting
whatever opportunities presented themselves. American pre-war doctrine had
been written in a vacuum, and was developed for a generic foe, rather than for the
fighting habits and style of the German army.
The chief tactical-operational problem facing the US army, as with all armies at
this time, was the coordination of fire and movement of large numbers of troops
over vast expanses of space, particularly in the rough terrain of the Argonne, and
in the face of stiffening German resistance. Although American officers spent
considerable time in the pre-war years debating issues, such as how to balance
border protection and coastal defence, tasks which seemed rather remote in 1918,
a number of them had followed tactical and technological developments in
140 The Evolution of Operational Art