Attorney General William Barr has already played a big role in draining the swamp — but he just put the final nail in the coffin of another awful Obama-era policy.

The Department of Justice announced it will launch an anti-trust probe into California automakers and will look into stripping away California’s ability to set its own fuel efficiency standards.

California appears to have colluded with four automakers to undercut the Trump administration rolling back Obama’s fuel efficiency standards.

Politico reports:

The Trump administration is opening new fronts in its legal war with California and much of the auto industry over clean air rules, taking steps toward punishing two of the major opponents of the president’s efforts to roll back Obama-era regulations.

The administration’s tactics include an expected effort to strip away California’s authority to set its own air pollution standards for cars and trucks, as well as a new Justice Department antitrust probe into four automakers that are voluntarily cooperating with the state’s clean air goals. The administration also warned California on Friday that its attempt to circumvent the administration’s rollback of federal rules is illegal.

All three actions represent a striking escalation of pressure from the administration, and come weeks after President Donald Trump publicly rebuked the “politically correct Automobile Companies” that are resisting his efforts to let them produce more gas-guzzling vehicles. Ford Motor Co., Honda, BMW and Volkswagen announced a voluntary agreement with California this summer to meet the state’s air pollution goals despite the Trump administration’s proposal to freeze fuel efficiency standards at their current level.

Trump’s allies said the president has been frustrated with the pace of rolling back the federal vehicle rules.

“The president is really angry that it’s taken so long to get this rule out and the public relations battle to win public support for what they’re doing is weakening because of the delay and the ability of California to sign up automakers onto their team,” said Myron Ebell, energy program director with the Competitive Enterprise Institute and former head of Trump’s EPA transition team. “To me it looks like it’s all a push coming from the president.”

In other words, California has turned into even more of a rogue state and has been allegedly colluding with automakers to avoid new rules put in place by Trump.

The far-left state continues to disobey the Trump administration and thinks they can do whatever they want — which is practically what they were allowed to do for eight years when Obama was in office.

California courts are stacked with Obama judges to hear their cases because the Democrats that run California know these liberal appointees can be counted on to hand down decisions that thwart Trump initiatives.

But Trump is not backing down and plans to go after the far-left state.