David Bossie slammed Mitt Romney for a scathing op-ed in which the incoming Utah senator criticized President Trump's leadership.

Romney, who will be sworn into the Senate on Thursday, wrote in the Washington Post piece, "His conduct over the past two years, particularly his actions this month, is evidence that the president has not risen to the mantle of the office."

Romney said not all of Trump's policies and appointments have been "misguided," but he said the president should demonstrate "the essential qualities of honesty and integrity, and elevate the national discourse with comity and mutual respect."

"As a nation, we have been blessed with presidents who have called on the greatness of the American spirit," he wrote. "With the nation so divided, resentful and angry, presidential leadership in qualities of character is indispensable. And it is in this province where the incumbent’s shortfall has been most glaring."

Trump responded on Twitter Tuesday morning, urging Romney to focus on issues like border security and to be a "team player."

Bossie, former Trump deputy campaign manager and a Fox News contributor, said on "Fox & Friends" Wednesday that this is "a pathetic attempt by Mitt Romney for relevancy."

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"Instead of trying to help this president, instead of trying to help the Republican Party, he wants to attack this president and really try ... and be the center of attention," Bossie said.

He said he's sick and tired of seeing people come to Washington, D.C. who want to be a part of the problem, not the solution.

"I'm very disappointed in Mitt Romney. I'm not surprised, but I'm disappointed," Bossie said.

He added that Romney -- a billionaire businessman and former Republican presidential nominee -- could be a greater GOP foil for Trump than retiring Sens. Bob Corker (R-Tenn.) and Jeff Flake (R-Ariz.), or Sen. John McCain (R-Ariz.), who passed away in August.

Watch more from Bossie above.

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