[citation needed] The attack at the Saint-Mihiel salient was part of a plan by Pershing in which he hoped that the Americans would break through the German lines and capture the fortified city of Metz.

It was the first large offensive launched mainly by the United States Army in World War I, and the attack caught the Germans in the process of retreating.

[6] This meant that their artillery was out of place and the American attack, coming up against disorganized German forces, proved more successful than expected.

[7] The attack on Metz was not realized, as the Supreme Allied Commander Ferdinand Foch ordered the American troops to march towards Sedan and Mézières, which would lead to the Meuse–Argonne offensive.

The area near St. Mihiel suffered much fighting:[9] In spite of French attacks, the German forces were able to retain this strategic location until the last months of the war.

General John Pershing thought that a successful Allied attack in the region of St. Mihiel, Metz, and Verdun would have a significant effect on the German Army.

For this, he placed his confidence in a young First Infantry Division Major, George Marshall, to move troops and supplies effectively throughout the battle.

Pershing had to persuade Marshal Foch (the supreme Allied military commander) to permit an American attack on the salient.

[15] Prior to the American operation, the Germans installed many in-depth series of trenches, wire obstacles, and machine-gun nests.

However, the German Army stationed in the area of St. Mihiel lacked sufficient manpower, firepower and effective leadership to launch a counter-attack of its own against the Allies.

[7] With Allied offensives to the north, the Germans decided to pull out of the St. Mihiel Salient and consolidate their forces near the Hindenburg Line.

[20] Chief of the United States Army Air Service Mason Patrick oversaw the organization of 28 air squadrons for the battle, with the French, British, and Italians contributing additional units to bring the total force numbers to 701 pursuit planes, 366 observation planes, 323 day bombers, and 91 night bombers.

[5] The French II Colonial Corps were successful in the attack on the apex and entered Saint-Mihiel on 15 September 1918, taking 4000 prisoners.

Pershing's operation included detailed plans for penetrating the Germans' trenches, using a combined arms approach to warfare.

Unlike other officers who commanded their soldiers from the rear, Colonel George S. Patton and Brigadier General Douglas MacArthur and their subordinates would lead their men from the front lines.

[5] American Captain Harry Truman, who commanded Battery D of the 129th Field Artillery Regiment during the battle, later became President of the United States.