America has not fought a war that we should have fought for except for maybeeee Afghanistan (and even then not to this crazy extent) since WW2.
The Korean was clearly justified as the North and the Commies were the clear aggressor. The only bad part was the North didnt fall as well which it would have if UN forces stopped after capturing Pyongyang instead of going to the Yalu River.
While getting a different Communist regime in a rump North Korea might have been possible had the UN not tried pushing to the Yalu, a total collapse just wasn't going to happen without that push.
Incidentally, Maduro's major concern isn't Guaidó per se but an internal coup that puts another PSUV member in nominal charge. That's the most likely outcome at this point in my opinion.