How fast can the auto industry go electric? Debate rages as the U.S. sets new rules

Tesla vehicles recharge in February in Corte Madera, Calif. The government wants to accelerate the transition to electric vehicle, but how fast the country can actually move is being hotly debated. (Justin Sullivan/Getty Images)

For car policy wonks, the Environmental Protection Agency's proposed new vehicle standards are this summer's hot blockbuster.

The surprisingly ambitious proposal unveiled earlier this year could mean that up to 67% of new vehicles sold by 2032 would need to be electric in order for carmakers to be in compliance. That would be a major step toward cutting U.S. greenhouse gas emissions.