Updated

As the shock begins to subside over South Carolina Gov. Mark Sanford's confession of infidelity, state lawmakers are starting to ask critical questions about whether the cheating governor can or should serve out his term.

One top Republican is calling outright for the two-term governor to step down. And other officials say the answers to several open questions will determine, in their minds, his fitness to stay on as governor.

Did he use tax dollars to carry on his affair with a mistress in Argentina?

How extensive was his effort to cover up his secret trip and was his staff complicit?

Why didn't Sanford make an attempt to transfer authority while he was out of state for a week?

Sanford tried to take a step toward reconciliation Thursday, releasing a statement saying he is reimbursing the state for part of an official trip he took last year to South America -- he admitted he spent part of that trip with his mistress in Argentina.

"While the purpose of this trip was an entirely professional and appropriate business development trip, I made a mistake while I was there in meeting with the woman who I was unfaithful to my wife with. That has raised some very legitimate concerns and questions, and as such I am going to reimburse the state for the full cost of the Argentina leg of this trip," Sanford said.

That might not soothe the concerns of state lawmakers.

State Democratic Party Chairwoman Carol Fowler released a statement late Thursday saying Sanford was "applying band-aids while the last of his credibility hemorrhages away."

"This latest admission raises more questions than it answers," she said, calling on him to "come clean" completely.

"The way I'm looking at it now after going home and sleeping on it. ... There's a lot of questions out there that need to be answered. ... I intend to get to the bottom of some of them," Republican state Sen. Jake Knotts told FOXNews.com.

"We need a person in that position that can start moving us forward," he said. "I'm beginning to believe that he didn't care about South Carolina. ... He's got to think about the embarrassment."

Knotts, a longtime Sanford critic, was taken aback by Sanford's decision to step down as chairman of the national Republican Governors Association while staying on as governor.

"Why should he be able to represent the whole state of South Carolina when he can't even justify in his own mind the ability to represent the Republican Governors Association?" he said.

Knotts said he wants to know whether Sanford committed an "impeachable offense," and that his seat should not remain "dormant" for the next year and a half.

Sanford's term is up at the end of 2010, and he cannot run again due to term limits.

Sen. Glenn McConnell, the Republican president pro tempore of the state Senate, on Thursday said party members want Sanford out, according to The Associated Press.

He had earlier raised legal questions about Sanford's trip and his fitness to serve.

"I would think that if the evidence indicates that there is a willful effort to circumvent the constitution, I think there would be a chorus of calls for him to resign," he said. He also called on Sanford to provide details about whether he used taxpayer money to facilitate the affair.

Sanford said Wednesday that his staff did not knowingly mislead the public about his whereabouts.

Sanford's office reportedly denies that he used state resources to further his affair, and Sanford attempted to clarify that point in his statement late Thursday on the 2008 trip. Sanford also said Wednesday that he paid for his latest plane ticket.

Politico.com reported Wednesday that Sanford has taken at least three taxpayer-funded trips to Argentina -- two in the 1990s, well before he supposedly knew his eventual mistress, and the one in 2008 which was paid for by the South Carolina Department of Commerce.

In an e-mail published by South Carolina's The State newspaper, Sanford's mistress described a romantic encounter the two had during that period.

The Politico.com report also said Sanford traveled to China and Brazil through the state's Commerce Department, logging a bill of $21,488 in travel expenses.

The Washington Post quoted a Sanford adviser as saying his boss is not considering resignation.

State Sen. Tom Davis, Sanford's former chief of staff, told FOX News that Sanford and his wife are "determined to work through this" but suggested his political fate remains to be written.

"I think South Carolinians are an incredibly forgiving people. Having said that, I think that South Carolinians will not tolerate hypocrites," he said. Davis said residents will need to see whether Sanford is "sincere" in his apology and whether he intends to make amends.

"I've known him for 30 years and he's a man of integrity and I think he will live up to that test, and I think he ought to be given a chance to live up to that test," Davis said.

South Carolina GOP Chairwoman Karen Floyd said Sanford's future "depends on how these next days come to fruition, and how he as a governor reaches out to the other elected officials and how the people in the state of South Carolina respond to him."

"We will take a look factually at the issues before us and ultimately the right decision will be made," she told FOX News.

But outside South Carolina, political strategists say resignation might be the only path forward.

"I don't think he does (stay in office)," said Republican strategist Brad Blakeman. "He needs to take himself out. ... because he needs to put his family above personal ambition. This guy obviously has bigger fish to fry than burdening the people of South Carolina with personal troubles which take him away from his government service."

Sanford was considered a potential 2012 presidential candidate, but the admission of the affair puts that in doubt as well.

"The question is he did he use state money?" said Pat Caddell, former Democratic pollster for former President Jimmy Carter. "He left the state without telling anybody. That is a problem. The problem is was there state money? He took several trips to Argentina supposedly for business things. ... If it was state money, he's going to have to go."

He added: "The legislature's out of session, we're finished for the year. He might hunker down and survive. It's still a very iffy question."

Meanwhile, national Republican leaders appear ready to change the subject.

House Minority Leader John Boehner avoided questions on Sanford.

"We've got a lot on our plate. I need to keep my members focused," Boehner said on Capitol Hill.

"I think as far as his remaining governor, it's up to the people of South Carolina, and that will play out," House Minority Whip Eric Cantor told FOX News.

"But, you know, really it's about trying to focus on the issues that people really care about. And I know this story will be in the news a little bit. But we here in Washington ought to be focusing on things that are really impacting people right now, which is the economy, which is jobs, health care and the rest," he said.

FOXNews.com's Judson Berger contributed to this report.