(Updated 4:45 p.m. ET)

Despite his capacity for self-sabotage and the public shunning of his own party, some well-heeled Republicans continue to believe that it's worth investing in former South Carolina Gov. Mark Sanford's comeback bid in Tuesday's special election for a vacant congressional seat in the Palmetto State.

During the last three weeks of the campaign, the unexpectedly competitive contest in a heavily GOP district between Sanford and Democrat Elizabeth Colbert Busch has become a magnet for big political spenders. Sanford, attempting a redemption run after a headline-making sex scandal that cost him his marriage and derailed his once-promising political career, has received more than $226,000 in last-minute donations of $1,000 or more, according to reports filed with the Federal Election Commission. As the race comes down the wire, Sanford has picked up the support of some prominent Republican women: Cosmetics executive Georgette Mosbacher, the ex-wife of former President George H.W. Bush's commerce secretary, Robert Mosbacher and a GOP bundler, chipped $2,600.  Independent Women's Voice, a political non-profit whose directors include prominent conservative Midge Decter, has spent more than $160,000 supporting Sanford and attacking Colbert Busch, Sunlight's Follow the Unlimited Money tracker shows.

As of Friday, the two candidates were tied in last-minute, big dollar fundraising, but Colbert Busch pulled ahead again with a haul of more than $90,000 in four-figure checks that day. She's now further ahead of Sanford in big contributors than she has been at any time in the last two weeks, including the days immediately after news of Sanford's trespass charges broke. The Democratic upstart's big contributors included labor unions and a political action committees of several Democratic members of Congress. All told, Colbert Busch, sister of TV satirist Stephen Colbert, has pulled more than $296,000 in four-figure checks in the closing two weeks of the campaign. Moreover, she has benefitted from nearly $900,000 in spending by the Democratic Congressional Campaign Committee and the Democratic House Majority PAC.

MORE:

• Sunlight reporting on the South Carolina special congressional election
• Complete list of last-minute donations of $1,000 or more to Sanford
• Complete list of last-minute donations of $1,000 or more to Colbert Busch

While no such GOP institutional support has been forthcoming for Sanford, his ability to stay in the money game appears to reflect a rethinking of the race by some Republican officials and givers. Several South Carolina Republicans who had cold-shouldered Sanford several weeks ago when reports surfaced that his ex-wife was suing him for trespass — most notably Sens. Lindsey Graham and Tim Scott — have since endorsed him. And Sanford's successor as governor, Nikki Haley, headlined a big closed-door fundraiser Wednesday in Charleston, S.C., w for his campaign.

Still, Colbert Busch likely continues to enjoy a substantial fundraising advantage. As of April 17, the last time the two candidates had to file a complete accounting of campaign finances, Colbert Busch was beating Sanfore by nearly 2-to-1 in fundraising, and of the $874,000 she raised, 39 percent came in donations under $200. By comparison, Sanford raised $453,000, of which 78 percent came in donations of $1,000 or more. While donations of $1,000 or more must be reported to the FEC within 48 hours during the closing days of a campaign, the candidates' total haul for the last two weeks won't be public until after Election Day. 

There is one prominent major donor whom Sanford has turned down: Hustler magazine Publisher Larry Flynt chastized Sanford for spurning his endorsement and contribution in an open letter. The  porn publisher sardonically hailed the former governor as "America's great sex pioneer," and promised not to respond to the shunning in kind.

"I will never divorce you," Flynt wrote.