A scathing barb from Sen. Kelly Loeffler (R-Ga.) accusing a fellow Republican of trying to “appease the left” was a rare example of a public intraparty feud amid President Trump’s impeachment trial.

But it was all the more head-scratching considering that the target of Loeffler’s attacks, Sen. Mitt Romney (R-Utah), has long been close to the appointed Georgia senator and the chamber’s newest member, with Loeffler and her husband being significant donors to Romney in the past.

What prompted the attack: Romney’s comments Monday that the testimony of former national security adviser John Bolton, details of whose unpublished manuscript were published by the New York Times and other news outlets, made his testimony before the Senate all the more relevant.

“I think it’s increasingly likely that other Republicans will join those of us who think we should hear from John Bolton,” Romney said Monday. “It’s important to be able to hear from John Bolton for us to be able to make an impartial judgment.”

The Utah senator and the party’s 2012 presidential nominee also spoke about the need to call witnesses during a closed-door party lunch, according to two officials familiar with his comments.

But Loeffler clearly disagreed.

“After 2 weeks, it’s clear that Democrats have no case for impeachment,” the tweet read. “Sadly, my colleague @SenatorRomney wants to appease the left by calling witnesses who will slander the @realDonaldTrump during their 15 minutes of fame. The circus is over. It’s time to move on! #gapol”

That was a strikingly different tone from a March 2013 article in Atlanta magazine, which jointly interviewed Loeffler and her husband, Jeffrey Sprecher.

When an interviewer noted that she gave a very large gift to Romney, Loeffler noted: “We both did.”

“Taking politics off the table, the Romneys are really lovely people, and well-intended,” Sprecher said. “We’d never known anybody that was running for president and actually had a friendship with them! And so it was easy to support a friend.”

Loeffler and Sprecher have been friends with the Romneys for more than a decade, with the Georgia couple having hosted several events for Romney at their Atlanta home, according to a person familiar with their relationship.

They were also significant donors to Romney’s failed presidential bid. Combined, Loeffler and Sprecher donated $1.5 million to Restore Our Future, a pro-Romney super PAC, in 2012, according to the Center for Responsive Politics.

Earlier this month, Romney also showed Loeffler the vaunted candy desk inside the Senate chamber — where sweets are stashed for senators to snack on while on the floor. He declined to strike back Monday when asked about Loeffler’s tweet.

“I think a good deal of Senator Loeffler and she and Jeff are good friends and have supported me time and time again,” Romney told reporters. “And I appreciate having her in the Senate.”

Loeffler faces a potentially difficult Republican primary if she is going to keep her seat past next January. Among the possible rivals is Rep. Douglas A. Collins (Ga.), the top Republican on the House Judiciary Committee and a leading Trump defender during the impeachment inquiry.

A spokeswoman for Romney declined to comment on Loeffler’s tweet, while a spokeswoman for Loeffler did not immediately return a request for comment on the two senators’ existing relationship.

Mike DeBonis contributed to this report.