By the first week of August 1870, Napoleon III had come under massive pressure to launch an offensive. This was not only the right thing for a Bonaparte to do politically, it was the only way strategically for France to preempt Prussia's superior numbers and organization, and, as Gramont continually reminded Leboeuf, the only way for France to lure the wary Austrians, Italians, and Danes into a French alliance. The problem, of course, was that France's advantage in the early stages of a Franco-Prussian war was presumptive and based on nothing more solid than the assumption that a larger peacetime army (France's) could mobilize more quickly than a smaller one that needed reserves (Prussia's). As it chanced, Moltke's army – regulars, reserves, and Landwehr – defeated that particular assumption, mobilizing faster than the French, absorbing Louis-Napoleon's half-hearted push across the Saar, and then swarming past it to crack the defensive French positions at Wissembourg, Froeschwiller, and Spicheren and push into France.

Truth be told, offensive operations were the last thing that the French ought to have been contemplating in the first week of August 1870. The synchronization of Gramont's bellicose foreign policy and the army's mobilization had been so utterly neglected that superhuman exertions were now required just to deploy the French army. On 1 August, eleven French guardsmen died of heatstroke marching from Nancy to Metz.