The reason I know he's gonna slink off is simple. The strong play is to simply sieze power and not care. He's not doing that, ergo he will not die on this hill.
Fixing the piles of shit that are DEF and EGR always costs more than a defeat device, and defeat makes the engine more efficient. Besides, federal prison buses roll coal nonstop and nobody gives a shit, as "Diesel Therapy" is their favorite trick for hurting dissidents.