Flake calls for 2020 Trump primary challenger

Sen. Jeff FlakeJeffrey (Jeff) Lane FlakeBernie Sanders to Trump: Firing Mueller 'an impeachable offense' Overnight Health Care: House passes .3T omnibus | Bill boosts funds for NIH, opioid treatment | Senators spar over ObamaCare fix | 'Right to Try' bill heads to the Senate The Hill's 12:30 Report MORE (R-Ariz.) called for a Republican to challenge President TrumpDonald John TrumpScarborough mocks 'Deflection Don' over transgender troop ban Pelosi condemns Trump's 'cowardly, disgusting' ban on transgender troops Trump moves to ban most transgender people from serving in military MORE in the 2020 election on Sunday during an interview with NBC's Chuck Todd on "Meet the Press."  

"Do you think he needs to be challenged from somebody who espouses your views?" Todd asked Flake. 

"Yes, I do. I do. I mean, it would be a tough go in a Republican primary. The Republican Party is the Trump party right now. But that's not to say it will stay that way," Flake said. 

The retiring Arizona has long been one of Trump's chief critics in the Republican Party, often lashing out at the president for his immigration and economic policies, as well as for his bombastic rhetoric. He criticized the Trump administration when announcing he would not run again for Senate.

Flake made similar comments earlier this month, and would not rule out a 2020 challenge to Trump. 

“I do think the president will have a challenge from the Republican Party, I think there should be,” Flake said. “I also think that there will be an independent challenge, particularly if the Democrats insist on putting somebody up from the far left of the party.”

Flake has stoked speculation about a potential 2020 bid with an upcoming visit to New Hampshire. 

Meanwhile, Trump last night jumped into full campaign mode at a rally in Pennsylvania for GOP congressional candidate Rick Saccone. 

Trump spent most of the event touting his accomplishments as president, and revealing his new campaign slogan "Keep America Great." 

"The tax bill was so massive, bigger than [Ronald] Reagan, biggest one done," Trump said. It is so big, he added, that "we are calling it tax reform" instead of a tax cut.

"This is where a nonpolitician is good. For 40 years they couldn't pass anything," the president continued. 

Trump is poised to face off against one of several Democratic hopefuls in 2020, which may include Sens. Elizabeth WarrenElizabeth Ann WarrenWarren battles Carson: Housing discrimination 'the scandal that should get you fired' Overnight Regulation: Omnibus includes deal on tip-pooling rule | Groups sue over rules for organic livestock | AT&T, DOJ make opening arguments in merger trial Warren presses Mulvaney, Azar on tip pooling MORE (D-Mass.), Kamala HarrisKamala Devi HarrisDems ask FTC to probe if other companies also obtained Facebook data Senate approves .3 trillion spending bill, sending to Trump Feinstein, Harris call for probe of ICE after employee resigns MORE (D-Calif.) or Bernie SandersBernard (Bernie) SandersCynthia Nixon: 'Sometimes a little naiveté is exactly what is needed' George Clooney writes Parkland students: 'You make me proud of my country again' Lesson from special election: Run on Social Security, Medicare and lower drug prices MORE (I-Vt.).