Our exulted Professor/President, Woodrow Wilson, having run for re-election in 1916 as the man "who kept us out of the war"............ended up having Congress declare war, 5 months after he was re-elected. He promised the Allies a '2 million man army'. Problem: We did not have a 2 million man army. We didn't have a 1 million man army. In the world's ranking of armies at the time, we came in at 16th..........BEHIND Portugal! As a result, the first division to be sent to France was the 1st Army Division. In order to send the 2nd Army Division, it was necessary to fill it out with Marines. Ever since, the 2nd Division and USMC have had a 'special relationship'. The original Army Div Commander died (IIRC while the troops were in transit to France), and the division was commanded by US Marine Corps generals, Brigadier General Charles A. Doyen and Major General John A. Lejeune. The first and only times that an Army division was commanded by a USMC General.
"No man's life, liberty, or property is safe, while Congress is in session." Mark Twain