On this day in 1917, The President asked Congress to Declare War and bring the US into the "War to End All Wars" . Congress did- but it wasn't. In approximately 18 Months - ( though the US Army and USMC didn't really get into the fight until My of 1918) the US suffered about 320,000 Casualties including 116,000 dead. This was a drop in the bucket compared to the casualties suffered by the other major combatants- somewhere around 11 Million Soldiers! which really gives you an appreciation of just what a cataclysmic event WW1 was for the western world.
https://history.state.gov/milestones/1914-1920/wwi
In fact, the vast majority of American casualties occurred in the last six months of the war. The Battle of the Meuse-Argonne lasted six weeks & cost 27,000 American dead 4500 dead per week! Another 100,000 were wounded. Amputated limbs, blindness, lungs reduced to 10% effectiveness due to poison gas, etc. Awful.
The worst day in British military history was certainly July 1, 1916. The first day of the Battle of the Somme. 20,000 dead and another 40,000 wounded in one day (10 times the dead on D-Day in 1944 among all the allies). More combat deaths in one day than the combined losses in the entire Indian Mutiny, Crimean War & Boer War (Britain's biggest 3 wars between the defeat of Napoleon & WW1) - combined. And the battle lasted five months. For what? British gains consisted of a few hundred yards of mud.
A very nasty, ugly war.
