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Posted on May 11, 2012 in Armchair Reading

CDG 51 – Battle of St. Mihiel, 1918

By Andrew H. Hershey

Click map to download pdf of larger version.Armchair General® takes you back to September 11, 1918, to eastern France, where you will play the role of U.S. Marine Corps Major General John A. Lejeune, commander of I Corps’ 2d Infantry Division. Your division, composed of U.S. Marines and Army infantrymen, has been given the mission to break through German trench lines in your sector and capture the town of Thiaucourt, the attack’s first-day objective. After taking Thiaucourt, your men will continue their advance.

LINK FROM PARA 8 to Western Front Trench Warfare.

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The Strategic Situation
By September 1918, four years of brutal trench warfare on World War I’s Western Front had produced millions of casualties but had not significantly altered the long front line stretching from Switzerland to the North Sea. German offensives that spring had pushed back British and French armies in Champagne and Picardy, but the Allied line had only been bent, not broken. The offensives cost the German army 700,000 casualties. While British and French losses were comparable, the arrival of over 1 million fresh American combat troops more than replaced Allied losses. Indeed, the growing American Expeditionary Force (AEF) under General John J. Pershing provided the Allies a means of reinvigorating offensive actions against the battered Germans that could at long last break the Western Front stalemate and win the war.

Pershing was eager to showcase AEF’s fighting ability and to demonstrate to skeptical British and French commanders the wisdom of his insistence on keeping American troops under American command and not parceled out to British and French divisions. Pershing selected the St. Mihiel salient, just west of the Meuse River and south of Verdun, as his U.S. 1st Army’s point of attack. Held by the Germans since September 1914, the 30-mile-wide salient jutted 15 miles into the Allied front line and threatened communications with the important French fortress of Verdun. About 500,000 American combat and support troops – organized into U.S. Army corps I, IV and V – were to attack September 12, 1918, to capture the salient.

Unlike your troops, the Germans are highly experienced in trench warfare – they have held the trench lines in this sector since 1914. Therefore you must devise a plan of attack that will give your men the best possible chance to defeat their seasoned opponents who are fighting from well-fortified positions.

St. Mihiel Salient
The salient’s point thrusts 15 miles into the Allied front line, to the town of St. Mihiel, forming a roughly triangular-shaped southwestward "bulge" that encompasses an area of over 200 square miles. German attacks in September 1914, aimed at seizing a foothold on the west bank of the Meuse River barrier and outflanking the formidable French fortress of Verdun, created this salient that has stubbornly resisted French attacks for four years.

The terrain inside the salient varies from higher ground (Heights of the Meuse) in the west and southwest, to gently rolling open country in the south, east and north dotted with patches of hardwood trees and numerous small villages. Recent and continuing rain has softened the ground throughout the salient, making movement by vehicles and horses over the muddy roads and waterlogged fields extremely difficult.

The German forces defending the salient consist of 10 infantry divisions assigned to 5th Army. Although these divisions are now chronically short of manpower – front-line infantry battalions number no more than 500 men – they still retain their full complement of supporting artillery and machine guns. Moreover, they occupy formidable in-depth defenses consisting of multiple trench lines and strongpoints protected by barbed-wire entanglements. The German unit defending U.S. 2d Infantry Division’s attack sector is 77th Reserve Infantry Division, composed of 257th, 419th and 332d infantry regiments.

German infantrymen are armed with bolt-action Mauser Gewehr 98 rifles – some of the war’s best small arms. They also carry hand grenades, bayonets, pistols, knives and even clubs to protect themselves during brutal hand-to-hand combat within the close confines of the front-line trenches. (See "Western Front Trench System" SIDEBAR.) Integrated throughout the enemy defenses are numerous Maxim-design Maschinengewehr 08s, machine guns capable of firing 500 rounds per minute to an effective range of 2,000 meters. German artillery support is impressive and deadly efficient, with numerous 77 mm field guns and 105 mm howitzers backed up by several battalions of large caliber heavy artillery. Unless the American pre-attack artillery bombardment knocks out the German artillery and machine-gun nests, U.S. infantrymen will be forced to advance across hundreds of meters of open ground under a blizzard of enemy fire just to reach the first trench line.

2D U.S. Infantry Division
Your 2d Infantry Division is an unusual formation within the AEF, composed of one brigade of U.S. Marines (5th and 6th Marine regiments) and one brigade of U.S. Army infantrymen (9th and 23d infantry regiments). Yet with a strength of 28,000 men, it is about the same size as a British, French or German corps. Your division, called a "square division" due to its organization of two large brigades of two regiments each, also includes a powerful artillery brigade – 30 battalions of 75 mm field guns, three batteries of 105 mm howitzers, 15 batteries of 155 mm howitzers, four batteries of 120 mm guns, and three batteries of long-range 155 mm guns. Each brigade also includes a machine-gun battalion (5th and 6th machine-gun battalions) with French-made M1914 Hotchkiss machine guns.

Each of your four regiments contains about 3,000 Marines or Soldiers organized into three 1,000-man battalions – about twice as many troops as in the German battalions you face. Your division’s infantry companies (four per battalion) each have 250 Marine or Army infantrymen.

Your division’s infantrymen carry either M1903 U.S. Springfield rifles or M1917 British-designed-U.S. manufactured rifles, both of which are bolt-action weapons firing caliber .30-06 ammunition. Your officers, machine-gunners and grenadiers (troops designated to storm enemy trenches and clear them with hand grenades) carry M1911 Colt .45-caliber semi-automatic pistols. Additional firepower in the infantry squads is provided by French Chauchat portable machine guns – weapons maddeningly prone to frequent jamming. The infantry companies also have 81 mm trench mortars for close-in fire support.

For this battle, I Corps is supported by U.S. Army 1st Provisional Tank Brigade, under the command of Lieutenant Colonel George S. Patton Jr. Patton’s brigade has several hundred French-built light (Renault FT17) and heavy (Schneider CA1) tanks, useful for accompanying infantry attacks against enemy strongpoints and machine-gun nests. The tanks, however, are subject to frequent mechanical breakdowns, quickly bog down in muddy terrain, and cannot easily negotiate wide trenches, streams or dense woods. You plan to use the tanks to support your infantry regiments during battle, but you can’t rely on them to lead the attack or to play a major role in breaking through German defenses. In fact, you fear the battlefield’s muddy terrain will prevent the tanks from making much, if any, forward progress. Indeed, they will likely struggle just to keep pace with the advancing infantrymen.

Limey, France
After graduating from the U.S. Naval Academy in 1888, you were commissioned in the U.S. Marine Corps in 1890. Your 30-year career has included service in the 1898 Spanish-American War, expeditionary operations in the Pacific and Caribbean, and important shore-duty assignments at Marine headquarters. You are an experienced officer with a well-earned, Corps-wide reputation as a "Marine’s Marine." After the United States entered World War I, you arrived in France in June 1918 and were promoted to major general July 1. On July 28, Pershing appointed you commander of the Marine-Army U.S. 2d Infantry Division.

Today, September 11, you have gathered your division staff and key unit commanders at your field headquarters in Limey, France, to hear three courses of action you are considering for tomorrow’s attack. Once the men arrive, you immediately get started.

"Before I explain the three options I am considering for our attack," you commence, "I want to tell you how the division will employ these ‘tanks’ the Army’s Colonel Patton is so enthusiastic about. Frankly, the mechanical unreliability of these vehicles and the muddy terrain we’ll be attacking across make me doubt the tanks will be able to keep up with our riflemen. However, in all three plans under consideration, I will assign some of Patton’s light and heavy tanks to accompany our infantry regiments – but don’t let the tanks slow down our attack. We must keep our riflemen moving forward as rapidly as possible at all costs, regardless of whether the tanks can keep up with them."

Course of Action One:

"Now, gentlemen," you continue, "the first plan I’m considering is to attack with three regiments in a wedge formation. At the point of the wedge will be 9th Infantry Regiment, with 5th and 6th Marine regiments following closely behind on each flank. The 5th and 6th machine-gun battalions will accompany the Marine flank regiments to maximize the machine guns’ fields of fire. I will keep 23d Regiment as division reserve to react to battlefield developments as the attack proceeds. Preceding the attack, both in this plan and in the other two courses of action, our artillery brigade will launch an intense four-hour bombardment concentrating on German artillery, machine-gun nests and strongpoints, and then it will shift its fire into a rolling barrage, paving the way for our attacking infantrymen when they go over the top."

Colonel Feland, commander of 5th Marine Regiment, speaks up first. "General, I fear that this deployment leaves the wedge’s leading regiment too exposed and highly vulnerable to the enemy’s concentrated firepower. If German artillery and machine-gun fire shatters 9th Regiment and stalls its advance, that could create a wide gap in our attack, isolating the flank regiments – my 5th Marines and Colonel Lee’s 6th Marines – and opening the door for a German counterattack to exploit the gap."

Colonel Lee, commander of 6th Marine Regiment, shakes his head and says, "Sir, I disagree with Feland. I think this tactical deployment provides great flexibility, especially for our two flank regiments. This plan gives us plenty of space and opportunity to maneuver, something that in my opinion – and I believe in General Pershing’s opinion – has so far been sadly lacking in our British and French comrades’ trench war attacks."

Course of Action Two:

"The next plan I am considering," you explain, "increases our attack’s shock effect and maximizes the division’s chances of punching through the enemy trench lines by stacking our two brigades in column formation. After our four-hour artillery bombardment, one brigade – 9th and 23d infantry regiments – will lead, with the second brigade – 5th and 6th Marines – following directly behind it. In this deployment, the two machine-gun battalions will position along the start line, providing covering fire and concentrating on the point of attack."

Major Messersmith, a 5th Marines battalion commander, ventures a comment. "Sir, my regimental commander, Colonel Feland, has already expressed his concern that your first plan will allow the Germans to concentrate all their artillery and machine-gun fire on our leading regiment. Doesn’t this second plan run an even greater risk of that, since it calls for our attack to advance along one narrow axis?"

Before you can reply, Colonel Lee, again shaking his head, answers Messersmith. "Major, there is a well-known principle of war called ‘mass’ – our British comrades call it ‘concentration’ – which entails applying overwhelming troop strength and firepower at a single point to achieve maximum impact against the enemy. This plan, to me, seems a perfect example of applying that principle in combat."

Course of Action Three:
"My final plan," you conclude, "is to attack with all four infantry regiments moving forward simultaneously in ‘line abreast’ formation immediately after the four-hour artillery bombardment ends. The two machine-gun battalions will be assigned one each to the right and left flank regiments so that their fire can sweep the ground ahead of the advancing infantrymen, and then they will displace forward as the infantry regiments progress. This plan maximizes the division’s full firepower, forces the defenders to distribute their artillery and machine-gun fire along the entire front, and increases our chances of finding some vulnerable point in the defenses to punch through."

Colonel Feland excitedly responds, "General, I support this plan wholeheartedly! It makes the best use of our advantages in troop strength and firepower and keeps German artillery and machine-gunners from concentrating on a single point."

Colonel Lee, however, does not share Feland’s enthusiasm. "General," he says, "this ‘line abreast’ deployment seems to be nothing more than the same unimaginative, massive frontal assaults that our British and French comrades have been using unsuccessfully for four long years now. This plan allows no room for the attacking regiments to maneuver, provides no chance to concentrate our forces at a vulnerable point in the enemy line to achieve a breakthrough, and dissipates – not maximizes – our firepower by spreading it along the entire German front line."

Although Feland appears ready to rebut his fellow regimental commander, you have heard enough to help you decide on a plan. Dismissing your men, you now ponder their comments as you pore over the tactical map of tomorrow’s battlefield. You have little time to waste. You must choose a course of action now.

What is your decision, General Lejeune?

Click here to download the pdf of CDG #51, Battle of St. Mihiel, 1918. Submit your answer and you might win a prize from Armchair General®.

Command Decision Game #51, "Battle of St. Mihiel, 1918" written by Andrew H. Hershey, appears with additional photos and illustrations in the July 2012 edition of Armchair General® magazine, where you’ll also find additional interactive articles based on the 101st Airborne in Iraq, 1991, and General Zachary Taylor at Monterrey, Mexico, 1846. On newsstands now.

Find earlier Command Decision Games by clicking here.

Andrew H. Hershey holds a doctorate in medieval history from the University of London. He contributes to the “USMC Gazette” and is a four-time winner of its Tactical Decision Game design contests. He also designs World War II tactical-level wargames for Heat of Battle and Le Franc Tireur.


  1. The artillery bombardment is key. Along with the intense fire and the creeping barrage I would include pauses in the barrage to entice the enemy forces out of their bunkers then hit them hard again making them question the actual time of the assault. I would also use the wedge formation plan but would add smaller wedges inside each regiment using battalions to have maximum support as well as keeping the men from getting bunched up. The colonels in charge of each battalion will have the freedom to move independently of one another taking advantage of terrain while allowing them to use their judgement to develop the situation and capture the objectives.

  2. The wedge attack seems to be the best course of action. It allows some flexibility and allows the forces to cover each other effectively.Also a wedge attack allows for concentrated firepower and overwhelming oncoming forces, which would make the already battered German from the powerful artillery bombardment severely demoralized and not fight to their true potential which is key when you are attacking entrenched forces. Also once our forces break through the German lines the should flank the entrenched germans and attack them from behind which would cause massive casualties to the German forces and further capitalize on the attack.


  1. CDG Command Center » Armchair General - [...] July 2012 Battle of St. Mihiel, 1918 PDF Pullout [...]

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