General Motors, Fiat Chrysler, Toyota, Hyundai and other major carmakers are backing the Trump administration in its bid to deny California its own fuel efficiency regulations.

The automakers are clearly not happy with California getting its way, especially after it and 22 other states sued in September to undo the administration’s determination that federal law bars California from coming up with its own emission standards and electric vehicle mandates, reports Autonews Europe.

This is a very complex situation, seen as how it could prompt furious backlash from Democrats and environmentalists alike. It’s also possible that if a Democrat wins the presidency in next year’s election, he or she could undo Trump’s actions on vehicle emissions and reinstate California’s right to set its own rules.

It’s interesting to note that Ford, Honda, BMW and the Volkswagen Group, are not interested in intervening, especially after announcing voluntary deals with California on emissions rules.

“It’s been the federal policy for the better part of 40 years that the federal government has the sole responsibility for regulating fuel economy standards, but it doesn’t have to get to that,” said John Bozzella, president and CEO of the Global Automakers trade group.

“We can still reach an agreement,” he added, as long as the companies still support a “middle ground” between California and the Trump administration.

Also read: EPA Revokes California’s Emissions Waiver, Launches “One National Program Rule”

Meanwhile, Sen. Tom Carper (D) of the Senate Environment and Public Works Committee, is definitely not pleased with the automakers backing Trump.

“Instead of choosing the responsible path forged by four automakers and the state of California, one that will move us toward the cleaner, alternative fuel vehicles of the future, these companies have chosen to head down a dead-end road,” said Carper in an official statement.