At a news conference hours after fellow Republican Lt. Gov. Andre Bauer called for him to step down, Sanford said the people of South Carolina want to move past the scandals and that he will finish the last 16 months of his term.
"I'm not going to be railroaded out of this office by political opponents or folks who were never fans of mine in the first place," Sanford said. "A lot of what is going on now is pure politics, plain and simple."
Bauer and Sanford have served two terms together but were elected separately and have never been friends.
Some Republicans have been reluctant to seek Sanford's resignation or impeachment because they do not want to give Bauer what would amount to a long-term tryout for the job.
If Sanford steps down before his term ends in January 2011, Bauer said he will promise not to run in 2010 so that is not an issue. Bauer considered making the same offer in June but never officially did.
"The serious misconduct that has been revealed along with lingering questions and continuing distractions make it virtually impossible for our state to solve the critical problems we're facing without a change in leadership," he said Wednesday.
House Republicans are expected to discuss impeachment this weekend. The House will likely launch those proceedings when lawmakers return for their regular session in January, though they could also hold a special session before then. Any House member can file a bill to impeach.
Sanford said heeding Bauer's call to resign would be like "heaven on earth" because it would get him out of the public eye, but it would not be right.
"Me hanging up the spurs 16 months out, as comfortable as that would be, as much as I might like to do that on a personal basis, it is wrong," he said.
Bauer said he tried to give Sanford the benefit of the doubt after he admitted his affair, but the state has been paralyzed by questions raised afterward about the legality of his official travel. Bauer said he is concerned that calls for Sanford's impeachment will dominate next year's legislative session instead of issues like the economy and job creation.
Bauer said he will go ahead with his candidacy if Sanford does not resign or lawmakers do not return to Columbia to force him out within 30 days. Term limits prevent Sanford from running for a third term.
Sacrificing the run for governor next year could boost Bauer's status in the state GOP but still allow the 40-year-old plenty of time for another election.
Republican Sen. David Thomas, a 2002 Bauer opponent whose Senate subcommittee is investigating Sanford's travels, said Bauer's decision would likely spur the House to action. Several Republicans have said they support impeachment.
"If he can have a successful time in the year as governor, then he sets himself up for a future race," Thomas said. "He's young. He can re-create himself to some degree as a successful governor." Francis Marion University political scientist Neal Thigpen said the offer could be disingenuous.
"My guess is, somehow the Bauer people have thought it through and figured this offer itself could be something - knowing Sanford would turn it down - would benefit him in some way in 2010," he said.
Sanford, who led his staff to believe he was hiking the Appalachian Trail, told The Associated Press his mistress was his soul mate. He said he visited her in Argentina during a 2008 trade mission planned by the state's Commerce Department and, after the publicity in June, reimbursed the state $3,300 for part of the trip.
AP investigations since have found Sanford used state planes for personal and political trips, which state law prohibits. He failed to disclose trips on private planes that ethics officials say should have been made public in campaign and ethics filings.
He also took pricey flights on commercial airlines for overseas trips despite a law requiring state employees to use lowest-cost travel.
The governor says he has done nothing wrong and he said Wednesday that his administration should be looked at in comparison with others. He gave no details but accused others of misdeeds including "folks" flying on the Concorde supersonic jet "in days past." The Concorde was taken out of service in 2003.
Sanford left without answering questions.
His wife, Jenny, has moved out of the governor's mansion with the couple's four sons but says she and her husband are working on their marriage.