In Volkswagen's Defense

From The American Thinker:

Specifically, it is possible to see their "defeat device" (basically a piece of software that detunes diesel engines during testing, but lets them run hot and clean in actual customer use) as an inspired bit of civil disobedience.

So, with that in mind, here's how Volkswagen could use the difference between the "de facto" real world application of the rule and the "de jure" world of law to defend themselves.

The legal defense is straightforward: the law generally requires these engines to pass EPA specified tests at the time of testing -- and they do. This is, in most jurisdictions, simple, black letter law: there is literally no legal substance to the charge against them.

The reality based defense, however, would be that the rule is known to be both unrealistic in economic and technical terms, and environmentally counterproductive. Basically VW would defend itself by attacking the rule maker and pushing the idea that the whole is thing is driven by the leftist agenda, not environmental concern.

Unique take, might work in front of a judge, but a California Jury, dead meat.