Oh man this is the one that sets me off every time. Not that I condone VW's cheating, but have you ever looked at how many diesel passenger cars are sold in the USA? It's effectively zero, and has been for a long, long time. Americans don't like diesel cars. They could be totally uncontrolled from an emissions standpoint and it would not make any difference at all.
It makes no sense to regulate emissions on diesel passenger cars in the USA.
The attitude that we can just throw it into the atmosphere and it won't hurt anything is exactly why we regulate emissions in the first place.
I'd be in favor of making diesel vehicles have to pass the exact same emissions requirements as gasoline vehicles.
That doesn't follow. Americans don't like diesel cars because emissions-compliant diesel cars are a massive pain in the ass. Diesel emissions treatment systems are a maintenance pain, as indicated by how many people with diesel trucks perform illegal emissions "deletes". The "magic" of VW's cheating was that it minimized or eliminated this pain, so all the owner was left with was the increased MPG, and this was pretty popular. It wasn't more popular because (1) plenty of people who would have considered a diesel with this ease-of-use would not have considered a VW, and (2) none of the other automakers could compete, because, you know, the cheating.