(CNN) - South Carolina Lt. Gov. Andre Bauer will call on Gov. Mark Sanford to resign in a press conference scheduled for Wednesday at noon, making him the highest ranking official in the state to do so, according to a source close to Bauer.
But Bauer - who has been plotting his entrance into the 2010 governor's race - will also pledge in the news conference not to seek the top office himself if Sanford does decide to step down in the coming weeks.
The lieutenant governor will send a letter to Sanford later today asking him to step down, a move that would elevate Bauer into the governor's mansion for the remainder of Sanford's term.
That prospect is an uncomfortable one for rival Republicans in the governor's race, who believe Bauer would gain an upper hand in the 2010 race as an incumbent. And because he stands to benefit directly, Bauer also risks appearing nakedly ambitious by asking Sanford to go.
But Bauer is promising not to enter the race if he assumes the governorship - a scenario he first floated to CNN in June after Sanford revealed an extramarital affair and came under fire from members of his own party.
"What it would do is it would get the politics out of it," Bauer told CNN about his proposal at the time. "The people that are so concerned for their own political future about running for governor, would no longer be worried if I came in and became governor, because I would just say.'You know what? This is bigger than politics. I will go and lead in for the next 18 months and not run for re-election.'"
Rivals to Bauer have noted that this isn't the first time he has promised to avoid future campaigning. In 2006, Bauer told The Greenville News that if were to win re-election in that year's campaign for lieutenant governor, he would not seek the governorship in 2010.
Bauer and Sanford did not run as a ticket and were elected separately in past elections.
The other Republicans running for governor are Attorney General Henry McMaster, Rep. Gresham Barrett, state Rep. Nikki Haley and state Sen. Larry Grooms.