(NEXSTAR) — This week’s bruising leadership fight in the Senate exposed simmering tension between Senate Minority Leader Mitch McConnell (R-Ky.) and Sen. Lindsey Graham (R-S.C.), former President Donald Trump’s closest ally in the Senate.

Graham, one of the Senate’s highest-profile Republicans, sharply criticized McConnell’s leadership of the Senate GOP conference during a private meeting this week.  

He then told reporters that he voted to elect Sen. Rick Scott (Fla.) as Senate Republican leader because he thought a change was needed.  

That earned Graham a sharp rebuke on Twitter Wednesday evening from Josh Holmes, McConnell’s former chief of staff and campaign manager, which some Republican senators saw as punishment for Graham criticizing McConnell’s leadership strategy during the lengthy private meeting at which Republican senators discussed why they fell short of expectations in the midterm election.  

And several GOP lawmakers and aides saw it as a sign that senators who challenged and criticized McConnell this week face potential repercussions from the leader’s powerful political network. 

Holmes, in his tweets, essentially accused Graham of flip-flopping on immigration reform, a potent issue for many GOP voters.  

Graham is positioning himself as a hard-liner on a possible immigration deal in the lame-duck Congress, declaring to Fox News: “There will be no deal on immigration until we secure the border.”

But Holmes, whose firm Cavalry LLC receives money from McConnell’s Senate campaign committee, pointed out that Graham was a leading proponent and coauthor of the comprehensive immigration reform bill the Senate passed in 2013, which provided a pathway to citizenship for 11 million immigrants lacking permanent legal status.  

“This dude literally spent the first half of his career championing amnesty,” Holmes wrote above a retweet of a Fox News graphic of Graham talking tough on immigration reform along with the caption “Strong as hell.”  

Holmes said he doesn’t speak for McConnell but pointed out that McConnell voted along with most Senate Republicans against the 2013 immigration bill, which conservative critics panned as “amnesty.”  

“I don’t speak for the leader but I do know he supports all his members. I also know that he is adamantly opposed to amnesty so that may be a difference of opinion on that particular issue.”  

McConnell’s allies within the Republican conference point out that Graham has evolved in other ways, such as how he views Trump.  

Graham famously warned his party in May of 2016: “If we nominate Trump, we will get destroyed … and we will deserve it.” 

But he swiftly maneuvered to become one of Trump’s closest allies after he was elected president.  

He explained his shift to Politico this way: “If you know anything about me, it’d be odd for me not to do this … This is to try to be relevant.”  

McConnell insisted Wednesday afternoon that he wasn’t angry at Scott or his backers.  

“I don’t own this job,” he said. “I’m not in any way offended by having an opponent or having a few votes in opposition.”  

Senators say Graham delivered an “impassioned critique” or even an “indictment” about what he characterized as “leadership’s failure to listen to voters.” 

“He thinks that the leadership and its agenda are not doing anything that actually appeals to our voters and reaches out to independents,” said one person familiar with the conversation, who described Graham as directly critical of McConnell.  

Republican senators confirmed that Graham delivered a blunt and forceful critique of McConnell’s leadership behind closed doors but questioned whether it changed anyone’s mind in the room.  

“Lindsey’s always outspoken. It doesn’t change whether you’re outside of the conference or inside the conference. He’s straightforward. There’s never a time in which you wonder where Lindsey stands on something,” said Sen. Mike Rounds (R-S.D.). 

“Everybody had a chance a chance to air their concerns, but I don’t think any minds were really changed,” he added.  

The South Carolina senator told reporters Wednesday that he thinks there needs to be “change” atop the Republican leadership but didn’t feel any personal misgivings against McConnell.  

“I voted for change, I voted for Rick. Nothing against Mitch, I just think we need change,” he told The Hill.  

But some Republican colleagues thought that Graham was acting on Trump’s behalf by attacking McConnell directly in front of the rest of the conference.  

Asked why Graham had criticized McConnell’s leadership so harshly, one GOP senator responded simply: “Trump, I assume.”  

CNN reported last week that Trump was trying to turn Republican anger over the failure to capture the Senate against McConnell by reaching out to allies, elected officials and incoming members of Congress.  

Graham is one of Trump’s closest confidants on the Hill.  

His attack on McConnell’s leadership acumen this week behind closed doors reminded Senate colleagues of his outspoken criticism he directed at McConnell in December, when McConnell negotiated a deal to allow Democrats to raise the debt ceiling. 

McConnell helped craft a deal to allow debt limit legislation to circumvent a Senate filibuster because he wanted to claim that Democrats would bear sole responsibility for expanding the nation’s borrowing authority.   

But Graham criticized McConnell for asking Republicans to vote for the measure that created a special pathway to raise the debt limit without having to overcome a filibuster after insisting for months that Democrats would have to do it entirely by themselves through the budget reconciliation process.  

Democrats instead used the budget reconciliation process in August to increase corporate taxes and enact new spending to fight climate change.  

“What I’m worried about is that for four months the Republican Senate said we would not lift a finger to help the Democrats raise the debt ceiling. We would make them use reconciliation,” Graham told “Fox News Sunday” host Chris Wallace in December.

“At the end, we did not make them use reconciliation, which changed the rules of the Senate in a House bill. I don’t like that a lot,” he said. “What we did is promised one thing and delivered another.”  

Graham was even more critical of McConnell during a private Republican conference meeting when he accused his leader of leaving Republicans exposed to attacks on the issue.

“He told colleagues that McConnell had “led them on a charge up a hill and they were getting shot in the back,” one GOP senator told The Hill at the time.  

Graham warned colleagues that Trump would come down hard on any GOP senators who voted for the special pathway to raise the debt limit.  

He warned that Trump “is going to be engaged on this issue.”  

True to Graham’s warning, Trump later lashed out at McConnell over the deal, declaring he “conceded, for absolutely nothing and for no reason, the powerful debt ceiling negotiating block, which was the Republicans’ first-class ticket for victory over the Democrats.” 

Scott sided with Graham and Trump in opposing the debt limit deal.  

“It’s really frustrating. Democrats want to go spend all this money, but they don’t want the responsibility to raise the debt ceiling. I don’t actually believe we ought to raise the debt ceiling. I think we ought to figure out how to live within our means,” Scott said at the time.