It began Tuesday night, when the AP reported that Sanford's ex-wife, Jenny Sanford, had filed a legal complaint alleging that her former husband had violated the terms of their divorce agreement and trespassed at her home. The next day, Sanford denied nothing and instead offered up a cockamamie explanation that revolved around not wanting his 14-year-old son to have to watch the Super Bowl alone.

By that point, though, the proverbial damage had already been done, in a fashion only the incomparable Mark Sanford could manage. By Wednesday afternoon, the National Republican Congressional Committee announced, on the record, that it was cutting Sanford off and wouldn't support his special election bid. (In a district this conservative, it's remarkable that Sanford would even need help in the first place.) Other right-wing groups like the Club for Growth quickly followed suit. Republican frustration with their own nominee has to be at record levels, but once again, it's a self-inflicted wound.

As the GOP was rushing out, though, Democrats rushed in. The House Majority PAC jumped first, throwing down the first $107,000 installment of a reported half-million dollar buy on a TV ad attacking Sanford over his ethical misdeeds, including his notorious 2009 hike on the Appalachian Trail. A day later, the Democratic Congressional Campaign Committee came in with $208,000 on a spot hitting the same themes, albeit much more darkly.

Now the progressive veterans organization VoteVets has also gotten into the act, with a $30,000 spot featuring a retired National Guard colonel who lacerates Sanford for his disappearing act. Says the officer, who did a tour of duty in Afghanistan when he was 58 years old and now lives in the district, "If I had abandoned my post, I could be court-martialed." It's a very searing way to frame the issue.

But of course, it's the trespassing making news right now, and that's obviously hurting Sanford. According to PPP, 51 percent of respondents harbor "serious" or "somewhat serious" doubts about his "fitness for public office," versus 44 percent who do not. This issue mostly divides along party lines, with Republicans largely unconcerned—but not entirely. It helps explain why Colbert Busch is pulling the support of 19 percent of self-identified Republicans while only 7 percent of Democrats say they're backing Sanford.

And apparently believing that when you're explaining, you're winning, Sanford has reduced himself to taking out a full-page ad in the Charleston Post and Courier featuring an incredibly lengthy account of his encounter with his wife at her home on Super Bowl Sunday as well as a deeply boring response to the various Democratic attack ads described above. He manages to compare his situation to the Alamo and even asks people to call him on his cell phone "if you have any further questions"! Sad doesn't begin to cover it.

Remember, though, that this is still extremely red turf: Only three Democrats sit in seats more Republican than this. So if Colbert Busch were to win, it would still be a remarkable upset—and an extremely tough district to hold in 2014. But you always have to play to win, and right now, Democrats have a shot, thanks to one man. Mark Sanford has proven once again what a singular force he is in American politics. With him, anything is possible.