Minnesota's vehicle emissions standards are poised to take effect next year, after the U.S. Supreme Court last week declined to take up a lawsuit filed by Minnesota auto dealers challenging the new state rule.

Championed by Gov. Tim Walz, Minnesota became the first state in the Midwest to adopt California's stricter tailpipe emissions standards in an effort to combat climate change.

The new rule, which encountered stiff opposition from Republicans, also includes a mandate for automakers to bolster their stock of all-electric and hybrid vehicles across the state.

But not everyone was on board. The Minnesota Auto Dealers Association (MADA) filed suit against the Minnesota Pollution Control Agency (MPCA), claiming regulatory overreach.

The Minnesota Court of Appeals upheld the state's clean-car mandate in January, and the state Supreme Court denied the case in May — prompting the appeal to the nation's highest court.

In its petition to the high court, MADA's lawyers claimed tying the state's air-quality regulations to California's is folly. "Minnesota is not California," the brief states. "It does not have California's smog and air pollution problems — so long as Canada keeps its forests from burning down."

MADA President Scott Lambert said auto dealers were disappointed with the U.S. Supreme Court's decision.

"We believe using California's rules is not a good fit for Minnesota," Lambert said in an email. "Minnesota dealers are happy to sell customers electric vehicles if those customers choose to purchase them. But we are not in favor of a mandate that requires us to stock vehicles that have very little demand."

Transportation is the state's leading source of global-warming emissions. The new clean-car rule takes effect Jan. 1, covering 2025 car and truck models.

Environmental advocates in Minnesota relished the legal win.

"Clean transportation is not only important for our health, but it's necessary for our economy," said J. Drake Hamilton, senior director for science policy for the St. Paul-based nonprofit Fresh Energy, in a news release. "Transitioning to a zero emissions vehicle fleet will provide good paying jobs and save consumers money at the pump."

On its website, MPCA notes the new rule does not apply to existing vehicles or used vehicles for sale, nor does it require emissions testing or the outright purchase of an electric vehicle (EV).

In a statement, MPCA spokeswoman Andrea Cournoyer applauded the U.S. Supreme Court's decision, saying the agency "continues to focus on implementing the standards and building out the EV charging infrastructure to provide Minnesotans with more access to cleaner vehicles and a network of charging stations making them more convenient to drive."

In addition to action on the state level, the Biden administration has set a goal calling for electric vehicles to comprise half of all new vehicle sales by 2030. In that vein, the administration has set aside $5 billion to help build out the nation's EV charging network — since taking office in 2021, the number of electric vehicle charging ports has increased by 40%.

Although most EV owners charge their vehicles at home, a recent study by the Pew Research Center found that an incomplete charging structure was one of the main obstacles would-be buyers cited when contemplating an EV purchase.

At the same time, 38% of those surveyed said they were "very" or "somewhat" likely to consider an EV when buying their next vehicle, the Pew study found.

Minnesota has launched a program for rebates of $2,500 and $600 for new and used EV purchases, respectively, although the program hasn't formally launched, according to the Department of Commerce website.

Federal law created rebates of $7,500 for new purchases of EVs and $4,000 for used vehicles, but they must be assembled in the United States.