From the founding of the US to 1918, the US had little to do in European affairs. From 1918 to 1939, the US was very much trying to stay out of Europe's business. It has only been since 1945 that the US has been a major player in European affairs. Maybe it's time we stopped doing that now that the raison d'etre for us being there no longer exists, eg., the Soviet Union. Russia is not some major threat as they can't even successfully invade and take a minor third tier nation on their own borders.
Maybe it's time we let the Europeans run their own show, even if it's straight into the ground.