Former Republican presidential nominee and incoming Utah Senator Mitt Romney wrote a scathing op-ed about Donald Trump in the Washington Post on Wednesday, saying the president’s character falls short of his office, leading Trump to wonder aloud if Romney is another “Flake.”

The “Flake” dig is a reference to outgoing Republican Arizona Senator Jeff Flake, who has oftentimes been at odds with the president and might consider running against Trump in 2020.

Romney says the president “made a deep descent in December,” leading to speculation that Trump may have more to worry about than Democrats taking control of the House of Representatives on Thursday, as he could have opposition from within his own party.

Per WaPo:

The Trump presidency made a deep descent in December. The departures of Defense Secretary Jim Mattis and White House Chief of Staff John F. Kelly, the appointment of senior persons of lesser experience, the abandonment of allies who fight beside us, and the president’s thoughtless claim that America has long been a “sucker” in world affairs all defined his presidency down.

Romney, who will be sworn in on Friday, also took exception with the president’s colorful insults at political opponents.

After he became the nominee, I hoped his campaign would refrain from resentment and name-calling. It did not. When he won the election, I hoped he would rise to the occasion. His early appointments of Rex Tillerson, Jeff Sessions, Nikki Haley, Gary Cohn, H.R. McMaster, Kelly and Mattis were encouraging. But, on balance, 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, perhaps laying the foundation for a 2020 primary run himself, said while he doesn’t agree with the president’s divisive behavior, he does agree with most of his policies.

It is not that all of the president’s policies have been misguided. He was right to align U.S. corporate taxes with those of global competitors, to strip out excessive regulations, to crack down on China’s unfair trade practices, to reform criminal justice and to appoint conservative judges. These are policies mainstream Republicans have promoted for years. But policies and appointments are only a part of a presidency.

To a great degree, a presidency shapes the public character of the nation. A president should unite us and inspire us to follow “our better angels.” A 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. 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.

The world is also watching. America has long been looked to for leadership. Our economic and military strength was part of that, of course, but our enduring commitment to principled conduct in foreign relations, and to the rights of all people to freedom and equal justice, was even more esteemed. Trump’s words and actions have caused dismay around the world. In a 2016 Pew Research Center poll, 84 percent of people in Germany, Britain, France, Canada and Sweden believed the American president would “do the right thing in world affairs.” One year later, that number had fallen to 16 percent.

Trump responded via Twitter, as per the usual, Wednesday morning.

“Here we go with Mitt Romney, but so fast! Question will be, is he a Flake?” Trump tweeted. “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!”

Editor’s note: Do you agree with Romney’s assessment of Trump’s behavior and if not, do you care if the president insults his detractors the way he does? Are you worried there will be opposition to the president from within the Republican party moving forward?