I don’t know by what means foreign countries would intervene in the US. They’d just ignore whatever is requested of them.
But it will increase US dependency on foreign countries in the long term. EVs are the future and if US manufacturers aren’t working on them then they’ll continue to lose market share to foreign companies.
The means would initially be similar to those used against other mildly-rogue regimes such those of Serbia and Mali: withdrawal of cooperation, fines, and limited sanctions.
If we get to the late 2040s and the rest of the world is within touching distance of net zero but the US remains as an extreme outlier in its refusal to decarbonise, then we could well see harsher measures such as those applied to the likes of Russia and Venezuela.
US is 350M people, let's say everyone is climate change sceptic and together with Russia, Australia and Saudi Arabia it totals to about 550M people.
In the rest of the world the idea that you can just just pump as much as smoke you like and it will magically disappear isn't popular. Maybe because they all had some polluting industry around that made them miserable or maybe because they live in dirty overcrowded cities and noticed that smog isn't pleasant or maybe because they don't have much fossil energy sources, they are generally not skeptical of the idea that "not polluting is good". Just as with vaccines or abortion, climate change or simply the desire to live in a clean environment isn't a divisive topic in most of the world.
So its going to be 8B people trying to compel 0.5B people to live in clean environments and take care of the output of their industries. I think the 8B will be able to do that one way or another.
But it will increase US dependency on foreign countries in the long term. EVs are the future and if US manufacturers aren’t working on them then they’ll continue to lose market share to foreign companies.