By Keith Laing

The governors of 23 U.S. states are pressuring the Trump administration to back down in a fight with California over gas mileage that has left automakers in a lurch about the fuel economy they will have to comply with going forward.

The governors, mostly Democrats, said in a letter dated Tuesday that they "stand together in calling for one strong, national clean car standard and support preserving state authority to protect our residents from vehicle pollution."

One notable absence among the signatories was Michigan Gov. Gretchen Whitmer.

"Strong vehicle standards protect our communities from unnecessary air pollution and fuel costs, and they address the largest source of carbon pollution in the United States," the governors wrote in a letter titled "The Nation's Clean Car Promise."

"Climate change is one of the foundational challenges of our time, and to truly address it, America needs cleaner and more efficient transportation solutions," the letter continued. "We must unite to ensure a strong, science-based national standard, in California and across the country, that increases year-over-year, provides certainty for automakers and consumers, reduces greenhouse gases, and protects public health."

The letter was signed by the governors of: California, Colorado, Connecticut, Delaware, Hawaii, Illinois, Maine, Maryland, Massachusetts, Minnesota, Montana, Nevada, New Jersey, New Mexico, New York, North Carolina, Oregon, Pennsylvania, Rhode Island, Vermont, Virginia, Washington and Wisconsin. The letter was also signed by the governor of Puerto Rico.

Tiffany Brown, a spokeswoman for Whitmer, said the governor is committed to reducing greenhouse gas emissions.

"Each governor of the U.S. Climate Alliance determines their own path for contributing to the collective goal of reducing emissions by 26-28% from 2005 levels by 2025," Brown said. "Michigan is in a unique position as the home of the U.S. auto industry and will continue to take ambitious climate action -- including in the transportation sector -- that is appropriate for the state, its economy and its communities."

The letter from the governors of 23 other states comes amid an intensifying fight between the Trump administration and California over the former's proposal to roll back stringent gas-mileage rules that were enacted under former President Barack Obama.

The Trump administration announced last year its intention to ease stringent gas-mileage rules that would have required fleets averaging nearly 55 miles per gallon by 2025. The administration proposed a freeze in the mandate after 2020, touching off a fierce battle with California, which helped to craft the Obama-era rules. The Trump administration's proposal to freeze gas mileage rules would keep a requirement automakers to average a fleetwide of 39 miles per gallon by 2020 in place until 2026.

The two sides attempted to negotiate a potential agreement, but the White House announced in February it was pulling out of the talks and moving forward with its proposed freeze in the gas mileage rules.

Automakers cheered the decision to reopen the so called mid-term review they were promised when the Obama-era gas mileage rules were agreed to in 2011. But they hoped the Trump administration would quickly reach an agreement with California on a new set of rules to prevent a lengthy legal battle that would leave the mpg requirements for the next half-decade in limbo.

"It is untenable to face a marketplace with different standards in different states, but it also untenable to face standards that rise so high that only a handful of electric vehicles can achieve them," the Alliance of Automobile Manufacturers, which lobbies for U.S. and foreign-owned automakers in Washington, said Tuesday. "We encourage both the federal government and states to come together and meet midway on a final rule that is good for the environment, achievable and consistent across the 50 states."

The Trump administration has floated the idea of moving revoke a longstanding waiver allowing California and other states to set their own stricter auto emissions standards. Thirteen states and Washington, D.C., have adopted California's mileage rules, meaning automakers could be left with one set of rules for a quarter of the country and another set for the remaining states.

Revoking California's waiver, which is ensconced in the Clean Air Act, would require a act of Congress that is unlikely with the U.S. House under the control of House Speaker Nancy Pelosi (D-Calif.).

Lawmakers who have been critical of the Trump administration's efforts to roll back the mpg rules applauded the governors who backed California in the mileage fight on Tuesday.

"For more than two years now, I have been urging the Trump administration to work with the state of California to strike a deal on fuel economy and greenhouse gas standards," U.S. Senator Tom Carper (D-Del.), top Democrat on the Senate Environment and Public Works Committee, said Tuesday. "But since the Trump Administration seems determined to put all environmental progress into reverse, automakers should make clear that they will not support this rollback by working directly with California and these 23 states to drive automobile technology into the future."

(c)2019 The Detroit News