More restrictive emissions laws are to protect individuals and task corporations to be better, so it seems good to let states enact their own more restrictive rules.
More restrictive emissions laws are to protect individuals and task corporations to be better, so it seems good to let states enact their own more restrictive rules.
Note that there has always been an exception to the rules: if you are out of state and your car it totaled you can buy a new non-California car and register it in California.
The actions California takes may be considered similar, especially (as someone below mentioned) if previously acceptable cars are not grandfathered in. There is also probably a good case to be made if California law has an effect, intended or not, on non-Californian states.
There is also a federal rule (good faith and something) that states must, in general, recognize the licenses of other states (marriage, drivers, etc; but notably not concealed carry, which I think will be tested again).
Personally, on the one hand I am for states rights and the environment and very much do not like how the interstate commerce clause is used. On the other, a lack of agreeable regulation is detrimental to the states (and having one state force that regulation does not seem fair).
If you were to instead ask "can you sell a vehicle that can't be registered" the answer is "yes." You can also make your own car and in so doing ignore most safety and emissions requirements.
There is a notable lack of small car manufacturers and a lack of case law on some of this. Some do mostly cosmetic work on existing models, and some sell "kits" and may help you assemble it "yourself" so as to qualify for a shopbuilt title.