The Trump administration plans to revoke the state’s authority to set rules that are stricter than Federal guidelines.

United States President Donald Trump and the state of California went to war on Wednesday over who should set the standards in the US for vehicle emissions and electric cars, foreshadowing a legal battle over environmental policy issues that will affect the car industry and consumers.

In a morning flurry of tweets, Trump confirmed he will revoke California’s authority to require car-makers to build cleaner vehicles than federal requirements demand.

The Republican president is counting on voters in truck-friendly heartland states to carry him to re-election in 2020, and he portrayed his decision as a win for consumers. Trump tweeted that vehicles would be “far less expensive” and “substantially SAFER”. California officials rejected both claims by the president.

Trump, who is in California this week, urged car-makers to back the action, which could also eliminate electric vehicle mandates in a dozen states that follow California’s regulatory lead.

The announcement will not immediately lead to revised emissions requirements, but this autumn, the Trump administration plans to announce a separate rule to dramatically roll back Obama-era fuel-efficiency standards agreed to with California, advancing a multipronged attack on the state’s efforts to reshape the mix of vehicles driven by Americans.

“Automakers should seize this opportunity because, without this alternative to California, you will be out of business,” Trump tweeted.

So far, none have publicly supported the revocation of California’s authority.

The Alliance of Automobile Manufacturers, a trade group representing General Motors Co, Toyota Motor Corp, Volkswagen AG, Ford Motor Co and others, declined to take a position on Trump’s revocation of California’s waiver, saying car-makers will review the decision “to get the full picture of how this impacts automakers, our workers and our customers.”

On Wednesday morning, California Governor Gavin Newsom, California Attorney General Xavier Becerra and Mary Nichols, the state’s top clean air regulator, appeared at a news conference in Sacramento and denounced Trump’s action as a “political vendetta” that risks damage to the climate and public health and would leave the US car industry behind in a global race to develop electric vehicle technology.

The Environmental Protection Agency and US Department of Transportation plan to announce on Thursday that the government is revoking an EPA waiver California received in 2013 to set state emissions rules and will hold a news conference to discuss the decision.

Newsom, Becerra, and Nichols said the state will go to court to challenge the administration’s action once it is official.

“This is the fight of a lifetime for us,” Nichols said. “We have to win this and I believe we will.”

Trump’s action came on the same day teenage climate activist Greta Thunberg was addressing the US Congress and urging legislators to treat climate change “as the existential crisis it is.”

When asked about Trump’s move, United Nations Secretary-General Antonio Guterres said on Wednesday he was opposed to it. “I’m strongly in favour of a decentralised approach to these measures and I’m strongly against any reduction of that decentralisation,” he told reporters. “I think it’s important – and this is true for many countries in the world – that cities and states and regions have a capacity to develop all positive measures in relation to climate action.”

Political battle

The fight over highly technical emissions rules will play out in the political arena where the issues are more visceral.

Trump and other administration officials have framed their decision as a move to protect consumers from regulatory mandates that would drive up the cost of vehicles, and force heartland truck owners to pay more for their vehicles to subsidise the sale of money-losing electric cars to wealthy coastal dwellers.

California officials, Democratic presidential candidates, and environmental groups countered that Trump’s action benefits only the oil industry.

Sierra Club Executive Director Michael Brune said the environmental group would file suit to challenge the move, calling it “nothing more than pure vindictiveness from an administration set on giving Big Oil a polluting pass at the expense of our climate and the wellbeing of American families.”

Americans will spend more on gassing up less efficient vehicles than they will save if new vehicle prices are kept down, California officials said. Nichols said Trump’s action threatened more asthma and more premature deaths from dirty air.

Car-makers are caught in the middle. While worried that California’s electric vehicle mandates will be costly, global car-makers have little choice but to develop battery-electric cars and trucks because Europe and China are pushing forward with rules requiring them.

“Every single one of these companies knows where the consumer is going and where the world is going … the elimination of the internal combustion engine,” Newsom said.

The car emissions battle is just one front in a widening battle between the Trump administration and California’s Democratic administration. The White House and the leaders of the largest US state have also locked horns over high-speed rail funding, border wall funding and immigration regulations.

Trump has also moved to roll back other Obama-era climate change regulations California’s leaders support.

Under Trump, federal regulators have backed freezing emissions requirements for new cars and trucks at 2020 levels through 2026. Administration officials say the final regulation will include a modest boost in annual efficiency requirements but far less than what the Obama administration set in 2012. At the time, California agreed to adopt the Obama rules rather than set its own standards.

The Obama-era rules called for a fleetwide fuel efficiency average of 46.7 miles per gallon (12.3 km/L) by 2025, with average annual increases of about five percent, compared with 37 mpg (15.7km/L) by 2026 under the Trump administration’s preferred option to freeze requirements.

The Trump plan’s preferred option would increase US oil consumption by about 500,000 barrels per day by the 2030s but reduce car-makers regulatory costs by more than $300bn.

California wants 15.4 percent of vehicle sales by 2025 to be EVs or other zero-emission vehicles and 10 other states have adopted those requirements.