The Supreme German commander, Helmuth von Moltke, had intended to execute a war strategy, the Schlieffen Plan, which required two things: the strength of the right-wing surge through France from the North, and speed . . . expeditious, unrelenting speed.
Moltke’s failure to win France at the Battle of the Marne, therefore, could in many ways be characterized not by the successful resistance of the French and British forces of the Entente, but rather by Moltke’s repeated distractions from the Schlieffen Plan’s two main requirements.
With respect to speed, it is true that both the British and the French successfully delayed the advancing German right wing time after time. Though they ultimately failed to make a stand directly in front of the right wing, they managed to buy time with which the French could summon more troops to the area. The major deciding factor, however, was Moltke’s insistence that the German First Army, the far right edge of all the German forces, remain linked with the army to its left, the German Second Army. The Second Army advanced more slowly than the second army, and its objectives were not as important as the First Army. Thus, by ensuring that the two armies remain linked, Moltke drastically slowed the advance of the all-important First Army, which, theoretically, might have seized Paris long before the French could send any reinforcements to the area.
With respect to strength, Moltke allowed himself to think that all of the German armies everywhere might prove as successful as the German First Army. He thus altered his strategy even while it was in motion, stripping troops from the right wing in order to strengthen other, less important sections of the German armies.
This all added up to a mid-September culmination where the German First Army had again pulverized the slapdash forces in its path, and threatened to advance on Paris. Because of the Second Army’s caution, however, a gap had developed between the First and Second Armies, and Moltke demanded that the First Army withdraw in order to shore up this potential weakness. It he had kept the First Army stronger, if he had allowed it to advance to the limits of its abilities, it could have continued to out-maneuver, out-march and out-fight any force that dared oppose it . . . it had up to that point, after all, been successful without exception.
Instead, the British and France had a victory . . . what few forces they had managed to shuttle up north in order to challenge the Germans were significant enough to cause Moltke to worry that he had to keep his line of armies contiguous.
Though the Germans had conquered much, Moltke understood that he had failed to defeat France in one grand stroke, and he did not relish the prospect of fighting a more drawn out war: he soon resigned as the supreme German military commander to be replaced by Erich von Falkenhayn.
The Entente forces would be allowed respite to organize themselves before the next phase of the war began.