Battle of Saint-Mihiel

Background

By the summer of 1918 the St Mihiel salient had stood for almost four years. German troops took the town and the Camp des Romains fort in September 1914 but were stopped short of Verdun, and the bulge they left cut communications between Nancy and Verdun. Repeated French attempts to reduce it had failed. The Americans activated their own First Army in August 1918, and John J. Pershing wanted a first independent operation that would reopen the road and rail links into Verdun and perhaps open the way towards the rail centre at Metz. He needed Marshal Foch's permission, and the plan had to fit alongside the larger Allied offensives then under way, and Foch had other plans for the American army.

The Germans, for their part, no longer wanted the salient. Their local forces were short of men and firepower, and the Allies later found a written German order, dated 8 September, to evacuate it. Army Detachment C had already begun to pull back when the Americans attacked; one account places the start of the withdrawal on 10 September, another has the troops starting to leave only the day before the offensive. Max von Gallwitz, whose army group included the salient, wrote afterwards that he gave the order to retire on his own responsibility, but too late to save many troops and much material. The battle therefore fell on a German army that was half in, half out of its positions, with an American army that had planned an assault on a fully held line.

The armies

The American First Army attacked with three US corps and a French corps under Pershing. On the southern face of the salient Hunter Liggett's I Corps and Joseph Dickman's IV Corps made the main attack, five and three divisions respectively in the front line, with the 78th and 3rd Divisions in reserve. George Cameron's V Corps, with the 26th Division and the French 15th Colonial Division, attacked the western face, and Ernest Blondlat's French II Colonial Corps held the apex. The sources disagree on numbers: a figure of 216,000 Americans and 110,000 French is given for the attack, another of some 248,000 Americans and French together, while Pershing's own count puts First Army at about 500,000, about 70,000 of them French, with reserves.

Armour and air power were the novelties. George Patton trained two American tank battalions with 144 French-built Renault FT light tanks, and the French added 275 more. Mason Patrick organised 28 American squadrons, and the Allied air force of some 1,481 aircraft, with Billy Mitchell in command, was the largest yet assembled. Against them stood Georg Fuchs's Army Detachment C: eight divisions and a brigade in the line and roughly two divisions in reserve, though Gallwitz counted seven in the salient, several understrength, including militia divisions and one Austro-Hungarian division. German strength is given as 75,000 or 85,000, with 213 aircraft. Weather was poor: five days of rain left roads muddy, drowned some tank engines and gave early trench foot.

The battle

12 September: the attack (CDB90 364 and 365). Allied guns opened in the small hours; after about four hours of preparation, I and IV Corps advanced at 0500 with light tanks, and V Corps began its attack on the western face at 0500 by one account and 0800 by another. The French II Colonial Corps made a holding attack at the apex. On the southern face I Corps reached its first objective before noon and Pershing then ordered a faster advance. In the 2nd Division sector the 3rd Brigade made the divisional opening attack and took Thiaucourt by noon after an advance of about 4.3 miles. Gallwitz recorded that the first deep advance, about 23 km, struck two German divisions on the southern side, and that his two reserve divisions behind that front could not restore the situation. One division, with Alsace-Lorraine men in its ranks, was scattered.

CDB90 also records a sub-engagement on the same day, LAHAYVILLE-BOIS DE LAMARCHE (365), from 0500 to 1730, in which a brigade under Brigadier General Bamford, the 2nd Brigade of the 1st Division, fought the German 47th Infantry Regiment. The draft has no narrative source for that fight beyond the CDB90 coding (see flags); a First Division history describes the division as the left, or marching, flank of the southern attack, with the longest advance to make.

13 September: closing the pocket. On the west face the 26th Division advanced from the west while the 1st Division came round from the east. Their patrols met near Hattonchatel and Vigneulles on 13 September, and by the afternoon every objective had been taken. In the centre the 5th and 6th Marines of the 2nd Division passed through the 3rd Brigade that evening and took the lead; the 89th Division took the abandoned village of Xammes and the 5th Marines took Jaulny and went beyond it.

14 to 16 September: stabilising the line. Pershing halted further advances so that American units could be moved to the Meuse-Argonne offensive. Foch, not Pershing, had decided the American army would be needed there, and the plan to push on towards Metz was set aside. Over the next two days the line west of the Moselle was pushed beyond the original objectives and then stabilised. The French II Colonial Corps entered Saint-Mihiel itself on 15 September and took about 4,000 prisoners, going on into the Woevre plain. On 15 September the Marines fought through the Bois de la Montagne, which they remembered as the most confusing fighting of their offensive. The 78th Division began relieving them that night and took command at 1000 on the 16th. Some accounts end the battle on 15 September; CDB90 and the Wikipedia dating run to the 16th.

Aftermath

The salient was gone in about two days. Counts of prisoners vary: about 13,000 in one account, nearly 16,000 in another, with 443 guns, 450 in another source, or about 200 in a third. American losses are given as about 7,000, a figure Pershing said related to the actual advance, or about 8,000. The Marine Corps counted 146 dead and 758 wounded in the 4th Brigade. German casualties are cited as 22,500, but I found no primary source for that.

The result is usually read two ways. The operation freed the Paris to Nancy railway, removed a threat to Verdun and Nancy, and showed that a US army could plan and run an offensive with its own staff, tanks and aircraft; Pershing's detailed operations order and combined-arms planning are the usual explanations for the success. Against that, the Germans were already leaving, and the Americans did not reach Metz. Foch redirected the American effort north-west, and within two weeks First Army was attacking in the Meuse-Argonne. The operation also left a footprint in American memory: it was the first use by Americans of the terms D-Day and H-Hour.

Wargaming it

St Mihiel is a good scenario for a large, scripted American assault, and a poor one for symmetrical play. The attacker has overwhelming numbers, light tanks and air support; the defender is brittle, short of men and trying to leave. The game is a timetable. At corps scale, with a hex or square of a kilometre or two, the attacker must reach Thiaucourt by noon on day one and link the 1st and 26th Divisions near Vigneulles and Hattonchatel on day two, while the defender tries to hold open the neck of the salient and pull back guns and stores.

The interesting levers are the withdrawal and the weather. Give the German player a rolling evacuation, in which units may disengage as a group rather than fight; give the Americans mud that slows tanks and artillery on a die roll. A variant that denies Loki, with the Germans standing and fighting in full strength, would test the American plan properly and is the obvious what-if. At battalion scale the 1st Division's 2nd Brigade fight at Lahayville and the Bois de Lamarche, or the 2nd Division's drive on Thiaucourt, make good small actions, but sources for them are thin. The air campaign can be run as a separate layer, with Mitchell's 1,481 aircraft against 213 German ones.

Maps and pictures