What policy did the United States follow at the start of ww1 in Europe

A strict policy of neutrality, the United States would not entangle itself with alliances with other nations.

After the First World War broke out, the United States adopted a policy of neutrality at first. The public opinion was not in a mood favorable to participation in a distant war fought by selfish European powers. So, president Woodrow Wilson would have had a very hard time trying to get Congress pass a declaration of war in 1914. It was only after the sinking of the British liner Lusitania in May 1915 by a German U-boat and the loss of 128 American lives that Americans started to change their mood and supported the Allied cause against Germany. The US finally entered WWI in 1917.