Over the course of his career, Lindsey Graham has had a penchant for picking tough political battles — and now that he’s in the Senate, he figures he’s got an even longer time to fight them.

“In my state, we change Senators about every 50 years,” said the folksy, baby-faced South Carolina Republican, who turns 49 on Friday. “So if I don’t screw up too badly, I’m probably going to be around for a while. And I can take the long view of things.”

Like his state’s most legendary Senator — Strom Thurmond, the Republican whom Graham succeeded in 2003 after Thurmond’s record 47-year Senate service — Graham has a disarming Southern drawl that belies the straight-talking and confident political pit bull he’s become.

Though Graham votes with his party 95 percent of the time and earned points with the GOP leadership for serving as a manager of President Bill Clinton’s impeachment trial in 1998, he’s also made some potentially risky moves by bucking his party’s establishment.

He was one of the ringleaders in the failed 1997 effort to oust then-Speaker Newt Gingrich (R-Ga.). He supported campaign-finance reform despite the opposition of many Republicans. He backed the primary presidential bid of Sen. John McCain (R-Ariz.) against George W. Bush in 2000. And most recently, he has emerged as one of the loudest Republican critics of Iraqi prisoner abuse at the hands of U.S. soldiers.

“I think he feels he needs to have at least some independent course at least on some issues,” said McCain. “I think he’s the next generation of [GOP] leadership.”

Sen. Saxby Chambliss (R-Ga.), a former House colleague and member of Graham’s Senate freshman class, sees Graham pulling off a difficult balancing act.

“You can’t call Lindsey a maverick because he certainly supports the Republican doctrine,” Chambliss said. “He has a difference of opinion and a certain amount of discretion, but I think that’s more of his South Carolina value-oriented background that makes him more of a statesman. … That’s why he’s right. If he wants to be here 50 years, he’ll be here 50 years.”

Graham says his eight years as a House Member gave him the confidence he needed to get a running start in the Senate. In just a year and a half in the Senate, he has forged bipartisan alliances, and even friendships, with the likes of Senate Minority Leader Tom Daschle (D-S.D.) and Sen. Hillary Rodham Clinton (D-N.Y.), the wife of the man he tried to impeach.

But what has provoked the most criticism from Republican colleagues is Graham’s quest to get to the bottom of what happened at Iraq’s Abu Ghraib prison and to understand how U.S. policies for prisoner treatment may have contributed to that abuse.

Though the furor over graphic photos showing the abuse of Iraqi detainees has begun to fade from newspaper headlines, Graham said in an recent interview that he still has numerous questions he wants answered by the top military and civilian brass at the Pentagon. And Graham may get his wish, because Senate Armed Services Chairman John Warner (R-Va.) expects to hold at least one more hearing on the prisoner abuse issue before July 23.

“While some may look at this as a political opportunity to beat up on [President] Bush, and some may think that we have to stand and fight back against anything a Democrat says, or compare ourselves to Saddam Hussein and say we’re not as bad, or point out that al Qaeda are the barbarians — I’m not playing that game,” Graham said. “I just want to know why that prison got so screwed up.”

Graham notes that his background uniquely positioned him as an expert once the news of Iraqi prisoner-abuse scandal broke. (He prefers to describe the actions in Abu Ghraib as “crimes.”)

Graham joined the Air Force shortly after earning his law degree in 1981. He went on to become a celebrated military attorney, and he still serves as a judge, and colonel, in the Air Force Reserve.

“I think he quickly focuses in on the fact that these questions are not partisan,” said Sen. Jack Reed (D-R.I.), an Army veteran who has become another sharp critic of prisoner abuse in Iraq. “Senator Graham and Senator McCain both have military experience, and they’re responding in terms of respect for the institutions of the military and the ethics of the military.”

Graham said he’s principally interested in the roles that were played by the Pentagon and the Justice Department in what he considers an erosion of the United States’ longstanding support for the Geneva Convention, the agreement that outlines the laws of war as well as interrogation tactics and basic standards of prisoner treatment.

“I want to know, legally, how we tried to play with the Geneva Convention,” he said. “For 50 years, this country has been the biggest advocate for the Geneva Convention for a reason — we want it to apply to our troops. We want to make sure that our people are taken care of if they fall into enemy hands. And how can you do that if you short-circuit the process?”

Though Graham voted with the majority of his party two weeks ago against a Democratic proposal to force the Justice Department to release memos on the treatment and interrogation of detainees, Graham said he would still work to get many of those memos released.

“If the Justice Department believes that they’re not going to be required to, or they’re not going to be pushed to give us information about how the policy was designed and implemented, I think they’re sadly mistaken,” said Graham. “If their position is we’re not going to give you anything — whoa, then I’ll be a little more strict.”

Still, Graham said he believes Senate Judiciary Chairman Orrin Hatch (R-Utah) will be able to convince Justice to hand over relevant documents without formal Congressional action.

On another vote — a Democratic plan to force the Defense Department to provide Congress with reports on prisoner interrogation techniques — Graham did buck his party’s position.

Some Republicans have accused Graham and other GOP Senators of grandstanding and of hurting President Bush’s re-election chances by continuing with his outspokenness. But Graham says he supports both Bush and Rumsfeld’s handling of the scandal.

Graham pointed out that Rumsfeld appeared responsive to the objections of military lawyers in crafting prisoner interrogation tactics, and he said he agrees with Bush that al Qaeda operatives and Taliban fighters in Afghanistan are not covered by the Geneva Convention.

“I agree with [the president’s] statement that any detainee should be treated humanely. My concern is that we’re trying to say that humane treatment replaces the Geneva Convention, and it doesn’t,” Graham said.

But when Graham believes he’s being unfairly criticized, he’s quick to strike back — no matter the person’s political affiliation.

In early May, when Vice President Cheney defended Rumsfeld’s leadership of the military by saying Congress “ought to get off his case” about prisoner abuse, Graham publicly rebuked the man who’s but a heartbeat away from the presidency.

“Nobody’s on their back,” said Graham at the time. “We’re doing our job.”

And during a Senate Armed Services hearing on May 12, Graham appeared to scold Sen. Jim Inhofe (R-Okla.) for saying, “I am probably not the only one up at this table who is more outraged by the outrage than we are by the treatment. … When we talk about the treatment of these prisoners, I would guess that these prisoners wake up every morning thanking Allah that Saddam Hussein is not in charge of these prisons.”

Graham responded, “I would just hope my colleagues can understand that when you say you’re the good guys, you’ve got to act like the good guys. … What are we fighting for … in Iraq? To be like Saddam Hussein? Is that what we’re fighting for?”

One GOP Congressional aide who requested anonymity said Graham has suffered little politically despite often irking party leaders with his unconventional stances.

“He has benefited from a very likable personality,” said the aide. “A lot of times if somebody has a heartfelt disagreement with the party line … you can always come home again as long as you don’t burn bridges.”

And the aide added that many in the party see Graham’s outspokeness as a hint of his larger political ambitions.

“In the Senate, talking, saying things, using your soap box is really how you make a name for yourself,” the aide said. “There’s a disincentive to towing the party line. … The incentive seems to be to express all their conflicted emotions all the time.”

Graham also is not shy about pointing out the potential hypocrisy of some fellow Republicans who failed to take a stronger stand on investigating the abuse.

“They get into the team sport of politics where it’s hard to be self-critical,” he said. “I can tell you right now that if President Clinton was in office, some of the people who are uncomfortable with me would be saying, ‘This shows you we don’t have enough people in the military. He’s destroyed the military. What’s going on in that prison, they’re just mimicking what he does.’ … But I am not going to play the team game about something this important to me.”

And given Senate rules that allow individual Members to exert extraordinary power, Graham appears to be relishing being a team of one, for now.

“The House is about gang warfare. If you were not in leadership or a senior member of a committee, the only way you got your say was to get a gang of people together to force your say,” said Graham. “In the Senate, you cannot be dealt out of the card game. … The rules of Senate allow people who are concerned and passionate to have their say.”

The Senate also allows for a bit more congeniality across the aisle than the House does. On the July 7 edition of ABC’s “Nightline,” Graham noted the political inexperience and relatively liberal views of Sen. John Edwards (N.C.), the newly named Democratic vice presidential candidate, but Graham, unlike many Republicans who blasted Edwards from the moment he was named, also praised his colleague from the state next door.

“Whatever differences I have with John Edwards, he is a good man,” Graham said on “Nightline.” “He will represent his party well. And if we underestimate him, we’ll be the big losers for it.”

Despite his hoped-for longevity in the Senate and his pending ascension to the senior-Senator position following the retirement of Sen. Fritz Hollings (D-S.C.) later this year, Graham said he has no designs on leadership posts.

“I don’t really have a desire to try to be a manager of other politicians,” he said. “That to me doesn’t have a lot of charm, but I respect those who want to do it. … I’m not at that point in my Senate career where I want to be limited, I guess. I want to be able to do creative things that a young Senator can do, that’s new to the body and that’s got some enthusiasm and hopefully a little bit of talent.”