A hundred years ago today, September 26th, the greatest artillery bombardment in U.S. history—more shells in a few hours than had been fired in the entire American Civil War—fell silent and 350,000 American soldiers got to their feet and began to advance across no-man’s-land toward the German trenches in the Meuse-Argonne. With the French and British stalled in their sectors, the Doughboys aimed to cut the German army’s principal supply line on the Western Front and end World War I.

The American role in the First World War is one of the great stories of the American Century, and yet it has largely vanished from view. Most historians tell us that the U.S. Army arrived too late on the Western Front to affect the war’s outcome, an outcome determined by Allied grit, better tactics, the British blockade of German ports, and, ultimately, German exhaustion and revolution.

It must be baldly stated: Germany would have won World War I had the U.S. Army not intervened in France in 1918. The French and British were barely hanging on in 1918. By year-end 1917, France had lost 3 million men in the war, Britain 2 million. The French army actually mutinied in 1917, half of its demoralized combat divisions refusing to attack the Germans. The British fared little better in 1917, losing 800,000 casualties in the course of a year that climaxed with the notorious three-month assault on the muddy heights of Passchendaele, where 300,000 British infantry fell to gain just two miles of ground.

By 1918, French reserves of military-aged recruits were literally a state secret; there were so few of them still alive. France maintained its 110 divisions in 1918 not by infusing them with new manpower – there was none – but by reducing the number of regiments in a French division from four to three. The British, barely maintaining 62 divisions on the Western Front, planned, in the course of 1918 – had the Americans not appeared – to reduce their divisions to thirty or fewer and essentially to abandon the ground war in Europe.

1918, eventually celebrated as the Allied “Year of Victory,” seemed initially far more promising for the Germans. The French army limped into the year, effectively out of men and in revolt against its officers; British divisions, 25 percent below their normal strength because of the awful casualties of Passchendaele, had not been reinforced. Prime Minister David Lloyd George refused to send replacements to Field Marshal Douglas Haig’s army on the Western Front, so controversial were Haig’s casualties. Lloyd George feared social revolution in Britain if casualties continued to mount, and lamented that Haig “had smothered the army in mud and blood.” ...