President Donald Trump has an “enemies list,” according to Politico, and it includes a senator with ties to BYU.

Trump has spoken of spending $10 million of his own money to make sure Arizona Sen. Jeff Flake gets defeated in the 2018 senate race, Politico reported.

Similarly, Trump sanctioned attacks against Republican Sen. Dean Heller, of Nevada, who was also critical of the president, according to Politico.

As Vox reported, Flake, who graduated from Brigham Young University, has spoken out against Trump during his presidency and in the 2016 campaign.

Flake will run again for the Senate in 2018, competing against former state Sen. Kelli Ward, who is pro-Trump. Jeff DeWit, former Trump campaign chief operating officer, and former state GOP chairman Robert Graham are also considering entering the race, according to Vox.

Republicans only have to defend eight seats in the 2018 election. Arizona could flip Democrat, though, according to Vox.

“Arizona, though a state with a heavy conservative tradition, is also a state with a large Hispanic population that Democrats hope to fire up as part of the resistance,” Vox reported.

Read more about the Trump’s impact on vulnerable Republicans on Vox.

Why does Trump want to defeat Flake? As The Hill reported, Flake called Trump’s initial travel ban “unacceptable,” saying it prevents people from wanting to move to the U.S.

"Enhancing long-term national security requires that we have a clear-eyed view of radical Islamic terrorism without ascribing radical Islamic terrorist views to all Muslims," Flake said in a statement in January.

FiveThirtyEight tracked Flake’s votes against Trump’s positions multiple times, showing that they disagreed twice on imposing sanctions on Russia and the 2017 fiscal appropriations bill.

Flake said he might have a tougher path ahead given his criticism of Trump, but it’s one he’s willing to embrace, according to The Washington Post.

“If I wanted an easier path through the primary, then I would line up more with where the president is,” he said. “But I think if you’re an elected official, you’ve got to do what you know what’s right. It’ll be a tougher path than I could have had, would have had, but I think I’ll get there.”