COLUMBIA - Under criticism for saying he might quit his Air Force Reserve unit, newly elected S.C. Gov. Mark Sanford said Tuesday he'll leave the governor's office for active military duty if his unit is called up.

It was unclear, however, if the Air Force would place Sanford on active duty, as he hasn't yet undergone required training. Sanford was commissioned a first lieutenant a year ago, but the courses he needs were filled before he could enroll.

"Since the unit has not been called up, and the governor has not attended all the classes yet that he needs to go to, that decision, of whether he'll be mobilized with this unit or not, will be made at that time," said Air Force Reserve spokeswoman Debra Baldwin.

The Air Force Reserve normally doesn't mobilize members who haven't been trained in their jobs, according to another spokesman, Col. Chris King.

In a letter to Lt. Gov. André Bauer released to the news media Tuesday, Sanford said he wanted to make clear his position on the issue. Bauer would temporarily take Sanford's place while he served on active duty.

"The bottom line for me is that I made a commitment and I am going to keep it," Sanford wrote. "Therefore, as to any orders I receive I will do just as anyone else in my unit and follow them."

Sanford's job description with the 315th Aeromedical Evacuation Squadron, headquartered at Charleston Air Force Base, is medical administration officer. That means he would coordinate medical airlifts aboard giant C-17 transport planes, which fly battle casualties to military hospitals in Germany or the United States.

Sanford said recently that the unit will be deployed to the Middle East before June. However, King has said the unit has not been notified it will be called up. If mobilized, it's unclear how long the unit might be deployed.

After his election in November, Sanford said that his duties as governor would prevent him from deploying with his unit, and that he was thinking of resigning his commission.

Those comments prompted criticism in letters to the editor columns across the state.

Some of the harshest criticism came from a retired officer in Sanford's reserve unit, Maj. Edgar Gomez.

"It occurs to me now that he has the governorship, this distasteful move at résumé padding has served its purpose," Gomez said in a letter to the Columbia State newspaper earlier this month.

Sanford spokesman Will Folks said the governor will address questions about his reserve duty at a press conference today.

Political questions surrounded news of Sanford's decision to join the Air Force last year, including whether the former congressman had used political influence to gain an officer's commission.

Sanford says he began checking into military service during his third U.S. House term. He said along the way he received no special treatment. At the time, Sanford said, he was not considering a gubernatorial bid.

Some older political figures including President Bush and former Vice President Dan Quayle joined the National Guard or the Reserves and avoided combat in Vietnam. Sanford was 12 years old when the draft ended in 1972.

Since joining the Air Force Reserve, Sanford has met his weekend drill obligations but has not completed either of his required training courses -- a two-week commissioned officers' school and a longer reserve health services administration course.

King, the Air Force Reserve spokesman, said the fact that Sanford hasn't been trained is no fault of his own. King said that all the slots in the two courses have been filled.

Bill Moore, a College of Charleston political scientist, said Sanford's decision "is a double-edged sword." Sanford may please some people who value military service and think Sanford should honor his commitment, but others may think his first commitment should be to his job as governor.

There are several examples of politicians leaving office to serve -- one high-profile example was Strom Thurmond, who joined the Army while serving as a state judge during World War II.

However, a chief executive officer of a state's leaving is different from a legislator's or judge's, Moore said. Thurmond left for a world war at a time when there was a draft. "Personally, as ... chief executive, it would seem to me that would be his primary obligation -- to serve the people of the state who elected him to this position. This is the type of conflict that didn't need to occur."

Moore said Sanford's decision creates "an intriguing scenario" and that in some ways is characteristic the new governor who prides himself in being a different kind of leader.

"I think Mark Sanford as governor will be one of surprises. He's not someone I see as predictable in terms of his behavior."