Not just destroy the environment. The US car industry will have a hard time developing and manufactoring cars which can be exported. Practically every other market will have stricter norms. China is betting big on electric cars, setting domestic restrictions forcing the Chinese car industry to innovate.

Then, the US will argue that the trade deficit is "unfair", while the real reason that markets will not buy US goods is that the products are anachronistic, sub-standard junk.