Trump had called Romney a "pompous 'a--'" in a response to Romney saying it was "appalling" to urge China and Ukraine to investigate former Vice President Joe Biden. The president took special aim at Romney's ability to "win," an apparent knock on his loss to former President Obama during the 2012 presidential election.
But for Scarborough, Romeny was a winner in certain ways that Trump wasn't.
"Mitt is a winner in so many ways that you will never be. Also, history will be kind to Senator Romney. You? Not so much," Scarborough tweeted on Saturday in response to Trump's post.
Scarborough, a frequent Trump critic, said the president would be remembered as the worst in American history.
"You’ll forever be remembered as the man who made James Buchanan the second worst president in American history. Congrats," he said.
Scarborough previously served as a Republican in the House of Representatives but left the party after Trump entered the White House.
His comments came as Trump defended himself from accusations that he inappropriately pressured Ukraine's president to investigate former Vice President Joe Biden.
"Somebody please wake up Mitt Romney and tell him that my conversation with the Ukrainian President was a congenial and very appropriate one, and my statement on China pertained to corruption, not politics. If Mitt worked this hard on Obama, he could have won. Sadly, he choked!" Trump tweeted on Saturday.
Trump's team has maintained that the president's attempts to influence Ukraine to investigate the Bidens' business activity in that country were a legitimate exercise of the president's authority.
Romney's comments were just the latest in a series of criticisms the former Republican presidential nominee has lobbed at the president.
Shortly after details surfaced about Trump's July call with Ukraine, in which he is said to have urged its president to probe the Bidens, Romney called for additional facts and claimed Trump's reported comments sounded "troubling in the extreme."
Giuliani responded to Romney by accusing him of being "bitter" about Trump.
"Look, Mitt, Trump did what you couldn't do. Trump has an ability to relate to people -- you don't," Giuliani said at the end of September.
At one point in 2019, Romney drew a rebuke from his niece Ronna Romney McDaniel, who serves as the chairwoman of the Republican National Committee. The senator had penned an op-ed in which he attacked Trump's conduct, saying he "has not risen to the mantle of the office."