House Speaker Paul Ryan has made an enemy, and her name is Sarah Palin. The vice presidential candidate turned reality TV star said she would back a primary challenger to the country’s top elected Republican over his ambivalent stance on presumptive Republican nominee Donald Trump.

“His political career is over but for a miracle because he has so disrespected the will of the people,” Palin told CNN on Sunday. “And as the leader of the GOP, the convention, certainly he is to remain neutral, and for him to already come out and say who he will not support was not a wise decision of his."

Ryan, R-Wis., is up for re-election this year. He is being challenged in the Republican primary by Paul Nehlen, a local businessman. Palin told CNN she would “do whatever I can for Paul Nehlen."

Palin, the 2008 Republican vice presidential candidate and a former governor of Alaska, offered Trump one of his first high-profile endorsements back in January. While most elected Republicans have since coalesced around their likely nominee, there have been some notable exceptions — Ryan being the most significant.

Ryan said on Thursday that he was “not ready” to endorse Trump just yet. But he left the door open to a later endorsement once he feels satisfied that Trump has successfully unified the Republican Party.

“I think the bulk of the burden on unifying the party will have to come from our presumptive nominee,” said Ryan.

Trump immediately fired back in a Friday statement saying he was “not ready to support Speaker Ryan’s agenda.” Nehlen promptly jumped in with a statement of his own, intended to draw a contrast with Paul Ryan’s ambivalence regarding Trump.

“If Mr. Trump is the nominee, I will support that decision, because it will have been the will of the voters that got him there,” said Nehlen on Friday.

Trump and Ryan will meet this Thursday to discuss their differences.

Ryan, a darling of the hard-right billionaire donors Charles and David Koch, is decidedly more conservative than Trump on issues related to taxation and the federal budget. But in recent months, he has invoked the ire of many grassroots conservative activists by pushing through a major spending bill and criticizing Trump’s proposed Muslim immigration ban. On Saturday, Nehlen told the conservative website Breitbart News that Ryan had “betrayed us all."

The primary race between Nehlen and Ryan will be decided in early August.