In his farewell address, the main thing that President George Washington warned the United States to avoid was "foreign entanglements."
When Washington wrote this (he didn't actually deliver this speech, he just had it published), he did not mean that the US should isolate itself. Instead, what he meant was that the country should not try to make permanent alliances. Instead, it should only enter into temporary alliances in the most extreme circumstances. Washington advised this because he did not want the young and relatively weak nation to get caught up in European wars such as the one between the British and the French that was soon to cause the US so much trouble.