Washington (CNN) Former California Republican Gov. Arnold Schwarzenegger took another jab at President Donald Trump on Thursday, following news that the administration plans to revoke a signature Obama-era environmental regulation.

"For 48 years -- since one of my heroes, then-Gov. Ronald Reagan, requested it -- California has had a waiver from the federal government to clean our own air," Schwarzenegger tweeted Thursday. "If the President thinks he can win this fight, he's out of his mind."

My statement on today's stupid, fake-conservative policy announcement that no one asked for. pic.twitter.com/ojAhWTFpDM — Arnold (@Schwarzenegger) August 2, 2018

The Trump administration wants to freeze a rule mandating that automakers work to make cars substantially more fuel efficient. It called its plan a "50-state fuel economy and tailpipe carbon dioxide emissions standard for passenger cars and light trucks."

The administration also proposed a withdrawal of California's Clean Air Act pre-emption waiver. California and about a dozen states follow its rules account for about a third of all the passenger vehicles sold in the United States.

In his tweet, Schwarzenegger described the proposal as a "stupid, fake-conservative policy announcement that no one asked for."