Certainly since World War II, General Motors has taken the stance that government should not regulate the automobile business more than necessary. GM has stated that position publicly and put its lobbying muscle behind it.
For the company to come out now not only disagreeing with a federal rollback of fuel economy standards but endorsing a federal mandate that it fought hard against when the measure was a California rule is an amazing turnaround.
It seems fairly transparent that GM favors a zero-emission vehicle mandate to help promote the electric vehicles that it manufactures and sells, whether the car-buying public wants them or not.
While there is plenty of discussion and disagreement about the Obama-era fuel economy and emission rules that the Trump administration has proposed to freeze at the 2020 level, no industry player has proposed instituting a national zero-emission vehicle program besides GM, which has a huge stake in EVs and is about to see the federal tax credit for its EVs disappear as it nears the statutory limit.
For GM to invite a bigger government role marks a big and surprising turnaround after years of resisting federal regulations on vehicle safety, emissions and fuel economy standards.
While GM's leaders might be arguing publicly that they don't want to have to build vehicles to satisfy two sets of regulations, they more likely want another helping of federal assistance by having the government mandate the purchase of EVs. GM's decision is certainly out of character and could diminish its lobbying influence in the future.
Having a range of EVs to choose from is quite different from having a federal law mandating the sale of a gradually increasing number of electrified vehicles.
A powerplant that consumers haven't embraced in any significant numbers seems like a poor choice for a government mandate.
It did not make sense in California, and it does not make sense now on a national scale.