Following American entry into the war in April 1917, the Germans decided that their only remaining chance of victory was to defeat the Allies before the United States could ship soldiers across the Atlantic and fully deploy its resources.

The German Army had gained a temporary advantage in numbers as nearly 50 divisions had been freed by the Russian defeat and withdrawal from the war with the Treaty of Brest-Litovsk.

No clear objective was established before the start of the offensives and once the operations were underway, the targets of the attacks were constantly changed, depending on the tactical situation.

The fast-moving stormtrooper units could not carry enough food and ammunition to sustain themselves for long, and the army could not move in supplies and reinforcements fast enough to assist them.

[7][page needed] Although Ludendorff was unsure whether the Americans would enter the war in strength, at a meeting of the Chiefs of Staff of the German armies on the Western Front on 11 November 1917, he decided to launch an offensive.

[8] The German government and Field Marshal Paul von Hindenburg, nominally the Chief of the General Staff, were not party to the planning process.

The stormtrooper tactic was to attack and disrupt enemy headquarters, artillery units and supply depots in the rear areas, as well as to occupy territory rapidly.

[13][incomplete short citation] Notwithstanding the effectiveness of the stormtroopers, the following German infantry often made attacks in large traditional waves and suffered heavy casualties.

Bruchmüller's tactics were made possible by the vast numbers of heavy guns—with correspondingly plentiful amounts of ammunition for them—which Germany possessed by 1918[citation needed].

In their turn, the Allies had developed defences in depth, reducing the proportion of troops in their front line and pulling reserves and supply dumps back beyond German artillery range.

In particular, in the sector held by the British Fifth Army, which they had recently taken over from French units, the defences were incomplete and there were too few troops to hold the complete position in depth.

His lack of a coherent strategy to accompany the new tactics was expressed in a remark to Rupprecht, Crown Prince of Bavaria—commander of one of his Army Groups—in which he stated, "We chop a hole.

At Arras on 28 March, he launched a hastily prepared attack (Operation Mars) against the left wing of the British Third Army, to try to widen the breach in the Allied lines.

In this sector, the British defences in depth were complete and fully manned, some of the opening German bombardment hit only empty positions and there was no fog to give cover to the attacking stormtroopers.

[23] After a few days, the German advance began to falter, as the infantry became exhausted and it became increasingly difficult to move artillery and supplies forward to support them.

It was, however, of little value; a Pyrrhic victory in terms of the casualties suffered by the crack troops, as the vital positions of Amiens and Arras remained in Allied hands.

[24] In terms of morale, the initial German jubilation at the successful opening of the offensive soon turned to disappointment, as it became clear that the attack had not achieved decisive results.

Michael had drawn British forces to defend Amiens, leaving the rail route through Hazebrouck and the approaches to the Channel ports of Calais, Boulogne and Dunkirk vulnerable.

They were being replaced in the front line by fresh British divisions, an operation that was planned to be completed on 9 April, the same day as the Germans attacked the sector.

[citation needed] The next day, the Germans widened their attack to the north, forcing the defenders of Armentières to withdraw before they were surrounded, and capturing most of Messines Ridge.

The commander of the British Expeditionary Force (BEF), Field Marshal Sir Douglas Haig, issued an "Order of the Day" on 11 April stating, "With our backs to the wall and believing in the justice of our cause, each one of us must fight on to the end.

The British abandoned the comparatively worthless territory they had captured at vast cost the previous year around Ypres, freeing several divisions to face the German attackers.

[citation needed] While Georgette ground to a halt, a new attack on French positions was planned to draw forces further away from the Channel and allow renewed German progress in the north.

The strategic objective remained to split the British and the French and gain victory before American forces could make their presence felt on the battlefield.

After the British had held off the Michael advance on the Somme, the US 1st Division was moved to reinforce the line in that sector in mid-April and launched their first attack of the war on Cantigny on 28 May 1918.

In this sector, the defences had not been developed in depth, mainly due to the obstinacy of the commander of the French Sixth Army, General Denis Auguste Duchêne.

There was a frenzied atmosphere in Paris, which German long-range guns had been shelling since 21 March, with many citizens fleeing and the government drawing up plans to evacuate to Bordeaux.

At Compiègne, a sudden French counter-attack on 11 June, by four divisions and 150 tanks (under General Charles Mangin) with no preliminary bombardment, caught the Germans by surprise and halted their advance.

Ludendorff now postponed Hagen and launched the German Seventh, First and Third Armies in the Friedensturm (Peace Offensive) of 15 July, a renewed attempt to draw Allied reserves south from Flanders and to expand the salient created by Blücher–Yorck eastwards.

[34] By July, the German superiority of numbers on the Western Front had sunk to 207 divisions to 203 Allied, a negligible lead which would be reversed as more American troops arrived.