What precedent did George Washington set as president of the unites states?

At the end of US President George Washington's last term he warned the nation to stay neutral in terms of the alliances, intrigues and wars of Europe. This was a mainstay of American foreign policy up until the second world war. In fact many Americans wanted no part of that war until the surprise attack on Pearl Harbor in 1941.

At the end of the first world war, the US Senate kept Washington's warning by voting NOT to join the League of Nations.