I keep seeing people looking forward to Trump cutting or ending US involvement in NATO & US support for Ukraine.

Hasn't anyone read a history book around here? Didn't the schools require them to study US history and government?

During the build up to WWI ("The Great War") and its early stages about a century ago, the US had its head in the sand. But as a late entrant that didn't have already its people and infrastructure being overrun or assaulted, the nation was able to come out of it in a good spot.

In the late 1930s through the mid 1940s, the same thing happened with WWII. The US's isolationism (and being separated from the combatants by oceans) helped keep things good until the attack on Pearl Harbor brought the war to the US.

In WWIII (in preparation since at least 2008--don't pretend it is avoidable, either), ignoring or failing to prepare will not prevent severe damage to infrastructure and population.