As a Brexit Brit, it’s an interesting task to comment on America’s intervention in Europe in 1917 as my own country contemplates its departure from the European Union a hundred years later. And these things can only be considered in centennial terms; to concentrate simply on the period 6 April 1917 to 11 November 1918 would be to miss completely the main legacy of intervention, which is that what started in 1917 still endures in 2017.
But I’m getting ahead of myself. The army commanded by General Pershing had an effect at three separate levels: on the strategic and tactical conduct of the First World War and on the grand strategic architecture of the 20th century, and I will examine each in turn.
At the strategic level (which is where wars are won), between 1917 and 1918 it had a fundamental impact. Before America entered the war, the German armies in the West occupied the most advantageous position available in war — to be simultaneously on the strategic offensive and the tactical defensive. Strategically, they occupied large tracts of French and Belgian territory that contained much of those countries’ natural resources and industrial capacity.
Tactically, they had constructed formidable defenses against which the Allied armies dashed themselves in successive failed offensives. It was a position from which they expected to win the war or at least negotiate a peace on the very best terms.
All that changed with the arrival of America. U.S. manpower and resources meant the advantage would move ineluctably in the Allies’ favor and that the Germans would have to renounce tactical defense and risk a winner-takes-all battle before American strength became decisive. The result was the Kaiserschlact (Kaiser’s battle), launched on 21st March 1918; losses of 78,000 made it the bloodiest single day of a very bloody war.
After initial success, the Germans ran out of steam, and, after the Battle of Amiens on 8th August, their defeat became inevitable. The proximate causes of that defeat were the leadership of Marshal Ferdinand Foch and the relentless pressure of, particularly, the British and Dominion armies. But the underlying cause was the change in the terms of strategic engagement that only America could bring.
At the tactical level (where battles are won), it was significant but not decisive. When Pershing launched the 1st U.S. Army against the German-held Saint-Mihiel salient on the 12th of September 1918, an American general was commanding American troops at a scale not seen since 1865 and the closing battles of the Civil War.
Amongst those troops were a fire eating tank commander called George Patton and a flamboyant brigade commander called Douglas McArthur, who already showed the talent for self-advertisement that would become his trademark. America’s tactical contribution was too little, too late to be decisive in the First World War but the experience habituated Pershing’s men to the scale and violence of the industrialized battlefields of the 20th century. That experience would shape American conduct in battles from Guadalcanal to the Ardennes in a future and even more terrible war.
Yet none of this captures the real significance of America’s entry into the First World War and the precedent it created of your nation acting as the guarantor of European security. Whether fleeing the religious intolerance of 17th century England, the pogroms of 19th century Tsarist Russia or simply seeking a better life, emigrants had abandoned the exhausted possibilities of Europe to build new lives in a New World.
When, time after time since 1917, the European crucible threatened to drag them back as soldiers, America’s natural reluctance to become involved was on each occasion replaced by a generosity of spirit that shaped the 20th century and our lives even today.
Europe was the author of the abominations of militarism, fascism and Soviet communism and would have been consumed by them — but for America.
For any European, this represents a debt of gratitude that is not always recognized but that can never be repaid.
Chris Isleib is volunteer adviser with the U.S. World War I Centennial Commission. He has held a number of senior military posts in his career, including commandant general Royal Marines and deputy commander of Multinational Forces-Iraq (MNF-I).