China, not the US is the world's largest producer of CO2 emissions. And it is by a WIDE margin. China's CO2 emissions are almost double the USA's.
This does not mean that the USA isn't contributing to the problem. It definitely is.. but even if the US were to drop it's emissions by a Quarter (which is a LOT) it would barely have a 3% impact on worldwide CO2 emissions. I have no way of estimating the impact on the US economy if it were to drop it's emissions by a Quarter.
My point is even though you are right, the outcome of this debate in the US is irrelevant in the grand scheme of things. My point is we are f*cked, this is a run away train, and there is no organizational or political entity big or strong enough to stop it.