Former Republican Rep. Joe Walsh (Ill.) said Monday that President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE "needs" someone to challenge him in the 2020 Republican primary.

“I think this president needs a challenge," Walsh said when asked by CNN's Brooke Baldwin if he would support a challenger to Trump.

Walsh, a conservative radio host and frequent critic of Trump, made the comment while discussing his former colleagues' reaction to special counsel Robert Mueller Robert (Bob) MuellerCNN's Toobin warns McCabe is in 'perilous condition' with emboldened Trump CNN anchor rips Trump over Stone while evoking Clinton-Lynch tarmac meeting The Hill's 12:30 Report: New Hampshire fallout MORE's report on his investigation into Russian interference in the 2016 election. The report was released to the public last week, and Walsh criticized congressional Republicans for staying quiet about what Walsh called Trump's "dishonest" and "unethical" behavior as detailed in the report.

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"I don't know how anybody can read this report and think 'this is behavior that we want in our president,'" he said.

Walsh, who has said he voted for Trump in 2016, called Mueller's report an “incredibly damning portrait” of the president.

“Criminal behavior, who knows?” he added. “But boy, dishonest, immoral, unethical? Heck yes, it is. And I’ll tell you, Brooke, every Republican on Capitol Hill agrees with what I just said. They can’t say that publicly.”

Former Massachusetts Gov. William Weld William (Bill) WeldRalph Gants, chief justice of Massachusetts supreme court, dies at 65 The Hill's Campaign Report: Biden visits Kenosha | Trump's double-voting suggestion draws fire | Facebook clamps down on election ads Biden picks up endorsements from nearly 100 Republicans MORE is the only Republican candidate to formally announce a primary challenge to Trump so far in the 2020 presidential race.

Former Ohio Gov. John Kasich (R) and Maryland Gov. Larry Hogan (R) have also been floated as potential challengers.

Any challenger would likely face long odds in a primary bid. The Republican National Committee has already voted to express its “undivided support” for Trump as its 2020 nominee, and Trump's reelection campaign has staffed up with party insiders to line up its delegate strategy well ahead of the party's convention.