President Trump Donald John TrumpBarr criticizes DOJ in speech declaring all agency power 'is invested in the attorney general' Military leaders asked about using heat ray on protesters outside White House: report Powell warns failure to reach COVID-19 deal could 'scar and damage' economy MORE on Wednesday responded to an op-ed written by Sen.-elect Mitt Romney Willard (Mitt) Mitt RomneyThe Memo: Warning signs flash for Trump on debates GOP votes to authorize subpoenas, depositions in Obama-era probe Overnight Defense: Trump hosts Israel, UAE, Bahrain for historic signing l Air Force reveals it secretly built and flew new fighter jet l Coronavirus creates delay in Pentagon research for alternative to 'forever chemicals' MORE (R-Utah), suggesting the incoming senator should be more supportive of his policies.

In a tweet, the president called on Romney to "focus on Border Security and so many other things where he can be helpful," while questioning whether he will be "a Flake," referencing Sen. Jeff Flake Jeffrey (Jeff) Lane FlakeRepublican former Michigan governor says he's voting for Biden Maybe they just don't like cowboys: The president is successful, some just don't like his style Bush endorsing Biden? Don't hold your breath MORE (R-Ariz.), a frequent Trump critic who did not run for reelection last year.

ADVERTISEMENT

"Here we go with Mitt Romney, but so fast! Question will be, is he a Flake? I hope not," Trump wrote Wednesday morning.

"Would much prefer that Mitt focus on Border Security and so many other things where he can be helpful. I won big, and he didn’t. He should be happy for all Republicans. Be a TEAM player & WIN!" he added.

Here we go with Mitt Romney, but so fast! Question will be, is he a Flake? I hope not. Would much prefer that Mitt focus on Border Security and so many other things where he can be helpful. I won big, and he didn’t. He should be happy for all Republicans. Be a TEAM player & WIN! — Donald J. Trump (@realDonaldTrump) January 2, 2019

The president's tweet came hours after Romney targeted him directly in a Washington Post op-ed, accusing him of a glaring "shortfall" in terms of character and leadership abilities.

"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," Romney wrote Tuesday.

"I do not intend to comment on every tweet or fault. But I will speak out against significant statements or actions that are divisive, racist, sexist, anti-immigrant, dishonest or destructive to democratic institutions," he continued.

Trump later doubled down on his comments during a Cabinet meeting at the White House.

“I wish Mitt could be more of a team player. I endorsed him and he thanked me profusely,” Trump said.

If Romney he said if he fought as hard against President Obama as he did against him, Trump said “he would have won the election.”

Elected in November to succeed the retiring Sen. Orrin Hatch Orrin Grant HatchBottom line Bottom line Senate GOP divided over whether they'd fill Supreme Court vacancy MORE (R-Utah), Romney is due to be sworn in as Utah's junior senator on Thursday.

Despite being a frequent critic of Trump's during the 2016 election, Romney thanked Trump for his support during his 2018 Senate run. He was briefly considered to be in the running to serve as Trump's secretary of State in 2017.

Jordan Fabian contributed.

This story was updated at 1:30 p.m.