For Graham, who spoke with POLITICO in an interview in his Capitol Hill office and views himself as a dealmaker, this is his sweet spot and one he's seizing on now in particular: He’s one of Trump’s biggest defenders on Capitol Hill but is still a go-to lawmaker for Democrats who want to work across the aisle on legislation. But his whipsawing around Washington could pose a threat to his credibility, particularly as he prepares for his reelection campaign and tries to evade a primary challenger.

Senate Minority Whip Dick Durbin (D-Ill.), who has criticized the South Carolina senator, laments his handling of the Judiciary Committee as well as the dearth of any legislation advancing out of it.

“I’m afraid he’s kind of stuck in the world of Mitch McConnell,” Durbin said, referencing the GOP leader’s prioritization of judicial confirmations in the Senate.

But Durbin, who also sits on the Judiciary Committee with Graham, added that he maintains a good working relationship with Graham that “shocks everyone at home," noting their work on immigration and criminal justice reform. And he concedes that in the GOP-controlled Senate, Graham “is the only show in town,” when it comes to finding a Republican senator to partner with.

Still, it can often be hard to pin Graham down.

When Trump announced last month he would withdraw troops from northern Syria, Graham warned it would be the “worst mistake” of his presidency, threatened Turkey with “crippling sanctions” for its incursion into Syria and teamed up with Sen. Chris Van Hollen (D-Md.) on a Turkish sanctions bill. But Graham also praised Trump for his handling of a ceasefire, and said the president has “rebuilt the military in the image of Ronald Reagan.”

Following the tragic mass shootings in Ohio and Texas over the summer that left dozens dead, Graham joined with Democratic senator and frequent Trump target Richard Blumenthal on legislation that would establish a grant program for states to restrict firearm access for people who pose a danger to themselves or others. But the bill has yet to be introduced.

Sen. Chris Coons (D-Del.), who worked with Graham on legislation to protect Mueller’s investigation, described his working relationship with Graham as “both challenging and rewarding.”

“The challenge is it’s the same guy,” Coons said. “It’s the same Senator Graham who is simultaneously doing things on Judiciary with which I strongly disagree and doing things on Foreign Relations and foreign aid matters that I appreciate. That’s part of the challenge of being able to work across the aisle.”

Despite moments of bipartisanship, Graham remains one of Trump’s biggest advocates on the Hill — a surprising turnaround for a senator who lost to Trump in the 2016 Republican primary and once referred to him as a “jackass.”

“I keep telling my colleagues don’t get sucked into the drama of the moment,” said Graham, who frequently golfs with the president . “The one thing about the president that I hope senators understand is he listens, he wants to be successful and he is not an ideologue.”

Perhaps nowhere is Graham’s loyalty to Trump more salient than when it comes to the House impeachment inquiry, which he has derided as a "lynching." And despite damning testimony from White House officials that Trump solicited help from the Ukrainian government to investigate the Bidens, Graham sees nothing wrong. He’s attacked the process, the media and even introduced a resolution condemning the House impeachment inquiry.

Trump rewarded him with a Twitter shoutout — and Graham declared victory after the House agreed to vote on the next steps forward of the impeachment inquiry last week.

Graham’s stance on Mueller's investigation into Russian interference is more complicated. Last year, he co-sponsored and supported legislation to protect Mueller but didn’t bring it for a vote once he became Judiciary Chairman, arguing that he didn’t think Trump would fire the special counsel.

“I supported legislation with Coons and Booker and Tillis to make sure Mueller couldn’t be removed without cause because I really didn’t know,” Graham said. “Mueller was the event for me. If Mueller found something where the Trump people actually had been working with the Russians unfairly, that would have been difficult.”

But when it comes to the House impeachment inquiry, Graham says “this whole Ukrainian BS is just sour grapes [from] sore losers.”

Graham is already getting heat for changing his views of Trump from Jaime Harrison, a former chair of the South Carolina Democratic Party vying for his Senate seat. Harrison describes Graham as a “political chameleon that changes his stripes and colors to benefit himself” and slammed him for getting “slim to none” done legislatively.

“We all know that Lindsey likes to be in the mix,” Harrison said. “It could be a gang of one and Lindsey Graham would want to be there if there’s a TV camera and a microphone. But at the end of the day how does that benefit the people of South Carolina?”

Senate Republicans are happy with Graham’s efforts to move judges through the Judiciary Committee. But Graham’ recent decision to delay a vote on Trump’s controversial judicial nominee Halil Suleyman “Sul” Ozerden — a close friend of acting White House chief of staff Mick Mulvaney — for an unusual fourth time prompted some confusion among Republican staffers, who questioned the repeated delays.

Graham is still working on Ozerden’s nomination though he acknowledged a letter from the NAACP denouncing the judge was a setback for getting Democratic support.

The South Carolina Republican insists that despite his close relationship with the president, he is still the “same guy” he was before Trump was elected. He argues that he has always cared about national security and that he worked on immigration issues long before Trump became president.

He agrees with Trump on enhancing border security and cracking down on asylum laws. He still wishes Trump had taken a compromise he struck last year with Durbin on immigration and continues to support a pathway to citizenship. He frequently notes Trump won the 2016 election, not him.

But Graham also likes to be in the mix on issues that are outside his usual purview. He tried a last-ditch effort with Sen. Bill Cassidy (R-La.) in 2017 to repeal Obamacare — despite no history of being a health care wonk. And on environmental issues, he partnered up with Sens. Joe Lieberman (I-Conn.) and John Kerry (D-Mass) on a clean energy bill that failed to move forward under President Barack Obama. Graham, who believes in climate change, now wants to create a global fund to address plastic pollution in the ocean.

When senators are asked about Graham, they most frequently describe him as "engaged."

“Who? Who is that?” quipped Sen. John Cornyn (R-Texas) when asked about Graham’s Senate style. He added it’s a “challenge for all of us trying to figure out how to prioritize but he seems to enjoy all of it."

While sitting in his office last week, Graham reflected on now-deceased senators he admired, including the late Sen. John McCain (R-Ariz.), and Sen. Ted Kennedy (D-Mass.), who he respected for his legislative skills. When asked about criticism that he's not getting enough legislation done, Graham responded “the people back home like the fact that I’m involved." He argues he’s had an impact on Trump’s policy in Syria and on impeachment.

“Putting together coalitions, arguing one day, working the next... I tell every new member of the Senate - you just got to understand that your enemy today can be your ally tomorrow," he said.