What were the effects of the US's isolationism?

Answer 1

US isolationism in WW1 essentially meant that the US public could not be persuaded to enter into a war which they saw as taking place far away from their shores, in the old European countries/nation states they, or their ancestors had left behind. It was not until the sinking of the Lusitania ( with the loss of innocent American lives) that President Woodrow Wilson was able to come to the assistance of the Western European Allies, against the German, Austro-Hungarian , and Ottoman Empires. It also meant that the delayed action allowed the Russian revolutionaries to gain popularity with the Russian people as the slaughter continued unabated, thereby adding to the factors responsible for the Russian Revolution and the overthrow of the Czar.