Officials in California said on Wednesday that they will fight the Trump administration's plans to revoke the state's authority to set its own emissions standards.

“There's no question, of course, that we will be in court," California Air Resources Board Chairwoman Mary Nichols said in a press conference.

“This is the fight of a lifetime. We have to win this,” she added.

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President Trump Donald John TrumpFederal prosecutor speaks out, says Barr 'has brought shame' on Justice Dept. Former Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick MORE announced earlier Wednesday that his administration will be removing California's tailpipe emissions waiver under the Clean Air Act, a decision that is expected to face fierce backlash in courts.

The Clean Air Act allows California to set more stringent emissions standards — something the state has done for decades. Thirteen other states chose to adopt those tougher standards.

California Gov. Gavin Newsom Gavin NewsomOVERNIGHT ENERGY: California seeks to sell only electric cars by 2035 | EPA threatens to close New York City office after Trump threats to 'anarchist' cities | House energy package sparks criticism from left and right California seeks to sell only electric cars by 2035 EPA head questions connection of climate change to natural disasters MORE (D) said Trump is trampling on states’ rights.

“That's not about states' rights. That's about bullying and intimidation. That's unethical,” he said, pointing to automakers' opposition to Trump’s measures.

"It’s about the oil industry, period. Full stop,” he added. “It's not about the car manufacturers; it’s not about consumers.”

California and the administration have been at loggerheads on a number of issues, in addition to vehicle emissions. The two sides have also failed to reach an agreement on a related standard on fuel economy. While the Trump administration has proposed rolling back Obama-era mileage goals, California has been working to get automakers to voluntarily meet higher fuel economy standards.

“I think that's what's leading to the president's unique frustration with California, because we are outsized in terms of our influence,” Newsom said.

California's leaders were light on details for the basis of their legal challenge to Trump's latest move, but state Attorney General Xavier Becerra Xavier BecerraState AGs condemn HUD rule allowing shelters to serve people on basis of biological sex OVERNIGHT ENERGY: Trump casts doubt on climate change science during briefing on wildfires | Biden attacks Trump's climate record amid Western wildfires, lays out his plan | 20 states sue EPA over methane emissions standards rollback 20 states sue EPA over methane emissions standards rollback MORE (D) said states also have due process rights.

“If the arguments in the president's tweets are the arguments they would use to propel this initiative, then we're looking pretty good,” Becerra said. “That's perhaps why they've taken so long to issue something they've been saying forever that they were going to do. They can't find a way to square the facts and the science with what they're trying to do.”

Nichols, meanwhile, said the administration's actions inhibit the state from dealing with climate change and could stop it from meeting federal air quality standards as pollution from vehicles contributes to dirtier air.

“The standards that we are now in the process of enforcing are necessary to protect the public health and welfare, not just because we care about the future of the planet or polar bears, it's because we actually need these extra clean cars in order to meet the health standards that are set by the federal government that we violate now on a very regular basis throughout Southern California and the San Joaquin Valley," she said.

This report was updated at 1:55 p.m.