President Trump called Democratic mega-donor Tom Steyer "wacky and totally unhinged" over his ad campaign calling for Trump's impeachment.

"Wacky & totally unhinged Tom Steyer, who has been fighting me and my Make America Great Again agenda from beginning, never wins elections!" the president tweeted.

Wacky & totally unhinged Tom Steyer, who has been fighting me and my Make America Great Again agenda from beginning, never wins elections! — Donald J. Trump (@realDonaldTrump) October 27, 2017

Steyer has blanketed cable news airwaves with $10 million in advertisements laying out the case for Trump's impeachment. In the ad, Steyer criticizes Trump's actions on health care, immigration and the environment and says a Republican Congress impeached Bill Clinton William (Bill) Jefferson ClintonGOP brushes back charges of hypocrisy in Supreme Court fight Battle lines drawn on precedent in Supreme Court fight Sunday shows - Ruth Bader Ginsburg's death dominates MORE for less serious conduct.

Tomorrow morning might be interesting: I'm told Tom Steyer's ad on impeaching Trump is going to play on Fox + Friends for the first time... — Gabriel Debenedetti (@gdebenedetti) October 25, 2017

Steyer also launched a digital ad buy on Thursday night, pressing House Minority Whip Steny Hoyer (D-Md.) to support impeaching Trump. The Facebook ads for the campaign, which were first shared with The Hill, encourage Hoyer’s constituents to sign Steyer’s petition, which calls on Congress to support impeaching the president.

The Democratic donor is active in environmental causes and has been seen as a possible primary challenger for Sen. Dianne Feinstein Dianne Emiel FeinsteinBiden leads Trump by 12 points among Catholic voters: poll Names to watch as Trump picks Ginsburg replacement on Supreme Court McConnell says Trump nominee to replace Ginsburg will get Senate vote MORE (D-Calif.).