(CNN) - South Carolina's lieutenant governor on Wednesday accused Gov. Mark Sanford of "serious misconduct" in office and said the time has come for the embattled governor to resign.
Andre Bauer is the highest-ranking official so far to call on Sanford to step down. He said he tried to remain supportive of the governor after he admitted to an extramarital affair in June, but subsequent investigations into Sanford's foreign and domestic travel expenses have become too much of a distraction for the state.
Several GOP lawmakers have said that Sanford, also a Republican, violated South Carolina law by paying for pricey seats on international flights and using state aircraft for personal and political purposes.
"Regrettably, we have reached a point where we must all put the interests of the people of South Carolina first," Bauer said at a news conference inside the state house in Columbia. "It is my opinion that the best interests of the people of South Carolina can no longer be served by the current administration."
Sanford has scheduled a news conference for 3:30 p.m. ET to respond to Bauer's comments.
If Sanford does resign, Bauer would become governor for the remainder of Sanford's term, which expires in January 2011.
But the lieutenant governor, who was elected separately from Sanford and is not a political ally of the governor, offered Sanford a deal: If the governor resigns and Bauer takes office, he said he will put aside his own political ambitions and not move forward with the 2010 gubernatorial bid he has long been planning.
Bauer's rivals for the 2010 Republican gubernatorial nomination have been uncomfortable with the prospect of Bauer assuming the top office and running as an incumbent in next year's GOP primary. Bauer and his team have accused rival Republican candidates and their political allies in the legislature of dragging their feet on the Sanford issue, in order to prevent Bauer from being promoted to the governorship.
"If taking me out of the governor's race makes this happen and we move forward quickly, then yes, I am willing to forgo the opportunity I may have to be governor for the next four to eight years," he said, describing his proposal as "selfless.
However, Bauer said his deal - which he first revealed to CNN in June - would only be on the table for the next month. If Sanford does not resign in the coming weeks, Bauer said, he will move forward with his plans to run for governor, even if Sanford is impeached and removed from office.
Investigations into the governor's travel expenses revealed that he spent thousands of dollars on business and first-class airline tickets for overseas flights, and used state aircraft for personal and political travel. Those probes were prompted by Sanford's disclosure in June that he had an affair with an Argentine woman.
Bauer called on the state legislature to take action on Sanford before the end of the year if he does not step down. Lawmakers will not be able to take formal action until the legislature re-convenes in January, unless a special session is called before then.
Members of the House Judiciary Committee have told CNN there are enough votes on the committee to send an impeachment motion to the floor of the House.
House Republicans are meeting this weekend in Myrtle Beach, South Carolina, for their annual retreat, and the impeachment matter is likely to dominate the agenda, according to those planning to attend.
The power of impeachment in South Carolina, according to the state constitution, is reserved for "cases of serious crimes or serious misconduct in office."
Impeachment requires a two-thirds vote in the House followed by a two-thirds vote in the Senate.
On Tuesday, Rep. Nathan Ballentine - a Sanford ally in the legislature - met with the governor privately and warned him that unless he steps down, House Republicans are likely to impeach him. Sanford rejected his plea.
"Barring some swing of momentum in his favor, I told him the writing is on the wall," Ballentine told CNN.
Sanford has said he and his family were working on healing after his admission about the affair. His wife, Jenny, and the couple's four sons recently moved out of the governor's mansion and back to their private home in Charleston for the beginning of the school year.