Might it have turned out the other way? By the start of 1917, the Central Powers and the Entente had fought each other to a bloody standstill at Verdun and the Somme. By the end of the year, the Russian revolutions had produced a Bolshevik regime seeking peace at any price, the Italians had been routed by Austro-Hungarian forces at Caporetto and half of all French army units had shown signs of mutiny. In November 1916, meanwhile, President Wilson had been re-elected on a pledge to keep the United States out of the war.

Victory thus seemed in reach for the Kaiser’s armies. Even as the Germans faced grinding hunger at home and at the front – the consequences of the brutally effective Allied naval blockade – they roused themselves for the Ludendorff Offensive in early 1918. The Russians had made their peace at