Hypothetically, let's say Greece and the United States enter the war two years earlier than they did (maybe the Lusitania is sunk two years earlier, idk).
How would the war and world have gone?
How would the war and world have gone?
Um. . . the Lusitania WAS sunk in 1915, dude.
Since Russia's still in the fight at this point, the Kaiser is now looking at a two front war with one of them receiving a massive infusion of manpower courtesy of the US. One of the big reasons why Germany was able to temporarily nullify the advantage the Allies had in thousands of fresh US troops on the Western Front IOTL was that the Russians had bowed out through Brest-Litovsk, which allowed for the transfer of veteran German units from the east to the west.
US entry at this point of the war may not be enough to convince the Central Powers to lay down their arms, but it should be sufficient to shorten the conflict's duration as a whole.