COLUMBIA, S.C. >> If South Carolina Gov. Nikki Haley is confirmed as President-elect Donald Trump’s pick for United Nations ambassador, her successor will be an entrenched veteran of the state’s GOP who as attorney general decided not to prosecute then-Gov. Mark Sanford for his spending after his disappearance to rendezvous with his mistress.

Lt. Gov. Henry McMaster, a 69-year-old known for his ability to disagree affably, would get the job he’s long wanted in the governorship. His leadership offers a sharp contrast in style if not in substance from Haley, the daughter of Indian immigrants and the nation’s youngest governor at 44, who hasn’t hesitated to publicly bash legislators who differed with her.

McMaster also was the nation’s first statewide officeholder to back Trump for president, in an endorsement before the state’s first-in-the-South presidential primary. The move stunned political observers, but McMaster’s support never wavered, despite Democrats’ calls to withdraw it.

He told The Associated Press last month he never regretted the endorsement.

“No ma’am, the more it went on, the more confident I was he was the man for the job,” he said in his characteristic, genteel drawl. He’s revealed little about what he would do as governor, and his office said he wasn’t available for an interview.

But as a savvy political insider, McMaster has forged strong relationships statewide.

He’s “a commonsense conservative — very reasonable, never abrasive,” said House Judiciary Chairman Greg Delleney, R-Chester. “He’s a realist, and he’s a gentleman, and I think he’s going to work with the General Assembly to get things done.”

Legislators hope McMaster’s entry could finally lead to passage of a comprehensive road-funding bill. Haley’s threats to veto anything with a gas tax increase stymied efforts for years.

Questioned by reporters after a meeting earlier this month, McMaster said, “We will make progress, great progress,” but gave no specifics.

In the 2010 GOP primary, Haley trounced McMaster and two other better-known men partly by running against the “good ol’ boy” network. Yet days after taking a 32-percentage-point beating, McMaster endorsed Haley with an exuberant “I’m all in!” and has been a close ally since. Beyond campaigning with her statewide, he arranged a series of private meetings between Haley and skeptical business leaders a week after she publicly chided the state Chamber of Commerce as a fan of bailouts and corporate welfare.

Bakari Sellers, a Democrat who lost to McMaster in the 2014 lieutenant governor’s race, contends McMaster “exemplifies the good ol’ boy network in South Carolina.”

“Henry’s been around a very long time. He’s the status quo,” said Sellers, a former state House member. “Courageous and visionary are not adjectives you use to describe Henry McMaster.”

Other longtime political adversaries applaud McMaster’s impending move.

“Henry is somebody who wants to do the right thing and move the state forward,” said former state Democratic Party Chairman Dick Harpootlian, who’s not one to pull punches. “If a good ol’ boy means somebody who remembers his friends and has a genial approach to governing, then I would take that as a compliment. He’s not going to rant and rave and pick fights. He’s not going to denigrate people publicly.”

McMaster began his political career in 1973 as an aide to then-U.S. Sen. Strom Thurmond. He led the state Republican Party for 10 years, while the GOP took control of the Legislature.

He frequently boasts of being President Ronald Reagan’s first appointment for U.S. attorney in 1981 and launched “Operation Jackpot,” an investigation into international drug smuggling that resulted in more than 100 convictions.

As state attorney general, he created a task force of officers posing as children to catch online sex predators and built an attorney network to prosecute criminal domestic violence. In 2010, he helped lead a multi-state challenge of President Barack Obama’s health care overhaul that allowed states to opt out of its intended Medicaid expansion — as South Carolina has steadfastly done.

In 2009, McMaster asked the state Ethics Commission to investigate Sanford after his disappearance to rendezvous with his mistress in Argentina brought scrutiny to his travels.

After Sanford paid $74,000 to resolve 37 civil charges, McMaster opted not to pursue criminal charges, saying Sanford’s use of first-class tickets, travel on state aircraft and questionable campaign reimbursements didn’t rise to a criminal level — and it was time for the state to move on.

A month after that announcement, McMaster lost to Haley.

Legislators say his decades-long relationship with many of them is an asset. GOP Senate Education Chairman John Courson, who met McMaster while at the University of South Carolina in the 1960s, said it helps that McMaster “understands the personalities in the Senate.”

“Across the board, among Democrats and Republicans, everybody is excited about him coming in — with the belief that he will have a desire to get things done and the ability to do so,” said House Minority Leader Todd Rutherford, D-Columbia.

Rep. James Smith, D-Columbia, said as a college student in the 1980s, he put out yard signs for McMaster.

“I think people who say he’s a good ol’ boy are missing what Henry’s all about,” he said. “Really, he’s about building strong relationships and treating people with respect and working for the future of our state.”