>... IMO we are the only existing superpower, which is why I think we should intervene in a limited way when a despot commits genocide on his own people.

And that is exactly the reason from my POV you should not establish a precedent of going in on your own. Even in this one there are grey areas - after Iraq believing some german "intelligence" is doubtful, even more so them claiming to have eavesdropped generals arguing for C weapons for some time with Assad.