On this day in 1914, as World War I erupted across Europe, President Woodrow Wilson declared that the United States would remain “impartial in thought as well as in action.” ... In February 1915, Germany declared unrestricted warfare against all ships, neutral or not, that entered the war zone around Britain.
The US was never actually 'neutral.' They didn't officially pick a side in the aspect at first but they did sell ammunition which was providing ammo to the Allies. Thus by doing so, they chose to help the Allies, picking a side.
