WASHINGTON (Reuters) - U.S. President Donald Trump on Wednesday thanked General Motors Co GM.N, Toyota Motor Corp 7203.T, Fiat Chrysler Automobiles NV FCHA.MI and other major automakers for "standing with" his efforts to bar California from setting its own vehicle emissions rules for cars and trucks.

FILE PHOTO: U.S. President Donald Trump delivers remarks in Chicago, Illinois, U.S., October 28, 2019. REUTERS/Leah Millis

“California has treated the Auto Industry very poorly for many years, harming Workers and Consumers,” Trump wrote on Twitter.

The automakers’ decision to side with the Trump administration follows legal challenges by California and 22 states and environmental groups in September.

Those challenges aim to undo the administration’s determination that federal law bars California from setting its own rigorous tailpipe emission standards and zero-emission vehicle mandates.

The decision to back Trump, disclosed in a filing with a U.S. appeals court late on Monday, has prompted a furious backlash from Democrats and environmentalists.

It also poses a risk for the automakers if a Democrat wins the White House in November 2020 and reverses Trump’s actions, allowing California to set its own rules and revert to the tougher national emissions standards of the Obama era.

The automakers did not immediately comment.

California Air Resource Board chief Mary Nichols on Tuesday criticized automakers after noting they tried a similar tactic previously. “GM, Toyota and Chrysler are repeating the same legal arguments they lost back in 2004, hoping for a different result. Definition of insanity?” she wrote on Twitter.

U.S. House Energy and Commerce Committee Chairman Frank Pallone, a Democrat, said on Twitter automakers “caving” to Trump’s “intimidation campaign won’t save these automakers” and added the decision to align with Trump’s “anti-climate agenda for the sake of a little short-term profit and reprieve from @POTUS’ Twitter tirades will do long-term damage, both to the automotive industry and to our country.”

Other automakers, such as Ford Motor Co F.N, Honda Motor Co 7267.T and Volkswagen AG VOWG_p.DE, which announced a voluntary deal with California in July on emissions rules, are not joining the bid to intervene on the administration's side.

The group backing Trump also includes Mazda Motor Corp 7261.T, Nissan Motor Co 7201.T, Kia Motors Corp 000270.KS and Subaru Co 9778.T.

In August 2018, the Trump administration proposed freezing fuel efficiency requirements at 2020 levels through 2026, reversing planned 5% annual increases.

The Obama-era rules called for a fleetwide fuel-efficiency average of 46.7 miles per gallon by 2026 compared with 37 mpg by 2026 under the Trump administration’s preferred option. The final requirements are expected to be ready by the end of the year.