This is the root of my problem. Yeah, the US _should_ be the leader on climate policy. But we've been failing for the last 20 years. At what point are we going to acknowledge that someone else needs to pick up the mantel. And as you've mentioned, it isn't like China is going to do it (you can shift my comment to China + US and the sentiment will hold true, but maybe I conveyed my thoughts poorly. Communication is difficult, especially over heated topics).
I genuinely believe that we can change course on climate policy, but it won’t happen in one or two national elections. Electing people who care about sustainability at every level of government is necessary for big changes to happen federally and internationally. We’ve got a lot of work to do!
If nobody has, then everyone has been failing, not just us. So the US might as well do the right thing "after we've tried everything else", as Churchill didn't actually say.
For nearly all of the time before China outstripped the US, the EU (if you include EU-27) was a larger contributor than the US anyway. And much of the early US emissions edge came before nuclear power was invented. Global warming itself was poorly understood prior to the 1960s: https://www.scientificamerican.com/article/discovery-of-glob...
A transition to nuclear would have helped, certainly! But climate change would not be "minor."
The US is influential, for better or worse; I think many people rightfully expect the US to be a leader on climate policy.
On your point, keep in mind that American consumption causes a tremendous amount of off-shore emissions. We have artificially “low” emissions because we outsource them to regions like Southeast Asia.