Within the Marine Corps the World War I Battle of Belleau Wood is legendary. Outside the Corps it is relatively unknown. Yet the battle was a turning point in the history of the Corps, clearly demonstrating that the Marines could operate at brigade strength in conventional warfare. Until then Marines were used principally as landing parties to secure a harbor or protect an American consulate, or as special operations and counterinsurgency forces. The Marines were swift and deadly, but large-scale operations were not their forte.
Before the Great War erupted the Marine Corps was only a few thousand strong. In 1916 Congress authorized an increase to 15,000; in May 1917, to 31,000. This would mean that the Corps could supply not only enough Marines for the Navy in the war but also enough Marines for two regiments of infantry to serve with the American Expeditionary Force. First, though, a grand recruiting campaign was necessary to inspire fighting-age men to join the Corps. The Marines’ typical appeal to the martial spirit of American males was effective, and thousands were soon swearing oaths at recruiting stations.
“The officers, from captain up, and fifty or so of the non-commissioned officers were old-time Marines,” said Col. Albertus Catlin, CO of the 6th Marine Regiment,
but the junior officers and all of the privates were new men....