If folks can get an equitable system working then that's great - otherwise I expect the US, India and China to bear the vast majority of the cost since those three nations all have an immense amount to lose if global warming gets more extreme.
Both India and China are in extremely weather sensitive areas with large populations and a government that would be unable to cope if food shortages became a thing and economic instability happened. America just doesn't want the hassle of being the golden egg if food shortages break down, it'll probably fair pretty well for quite some time, but the 40% of Americans that are obese will be poorly situated to survive in extreme weather events.
My response is:
1. China is doing stuff. Not enough perhaps, but arguably more than we are.
2. Who are we to say anything? Canada has the highest per capita emissions in the world. If anybody should be first, shouldn't it be us?
But the free riding problem is still real. "Climate clubs" would completely demolish the "but China" problem.