GM has abruptly dropped its support for a lawsuit challenging the authority of the California Air Resources Board (CARB) to put forth its own vehicle emissions requirements, distinctly separate from those set forth by the Environmental Protection Agency. CARB is the only organization with the ability to set its own emissions standards, although there are more than a dozen other states that have opted into following CARB's regulations instead of the EPA's.

The move makes some sense given GM's renewed focus on pure-electric propulsion, which calls for the introduction of multiple brand new pure-electric vehicles like the GMC Hummer and Cadillac Lyriq - vehicles that could give the automaker a leg up in meeting CARB's stricter emissions standards. A statement from the company, however, made it sound more like a simple change of heart inspired in part by the coming change in presidential administrations.

"We believe the ambitious electrification goals of the President-elect, California, and General Motors are aligned to address climate change by drastically reducing automobile emissions," GM's CEO, Mary Barra, said in a statement. "To better foster the necessary dialogue, we are immediately withdrawing from the preemption litigation and inviting other automakers to join us."

GM is just one of over a dozen automakers to have signaled their support for the Trump administration's lawsuit challenging the legality of CARB's arrangement - a list that also includes Toyota and Fiat Chrysler Automobiles. Apart from stripping CARB of its power to set its own emissions regulations, creating a single unified nationwide standard, the lawsuit sought to freeze national fuel mileage requirements at their current level rather than allowing them to continue increasing aggressively to 36 miles per gallon by 2025.

As proudly and often as GM touts its "zero crashes, zero emissions, zero congestion" mission, the company's support for the Trump administration's suit reflect the realities of where the company is today. Some of the hottest properties in the GM portfolio - trucks like the Chevrolet Silverado and SUVs like the all-new GMC Yukon and Cadillac Escalade - happen to be quite large, heavy vehicles with available V8 power. The small-block has gotten almost impossibly power-dense and efficient in recent years, but that hasn't stopped GM from consistently being one of the lowest-ranked major global automakers in terms of average fuel economy.