And despite many people dismissing her chances in a pretty conservative South Carolina congressional district, nobody should be counting her out completely.
The district, formerly held by appointed Sen. Tim Scott (R-S.C.), went overwhelmingly for Mitt Romney last year, 58 percent of 40 percent. It also gave Sen. John McCain (R-Ariz.) a big win in 2008, 56 percent to 42 percent.
That reality means Republicans will be favored, without question. But there are a few factors that could well keep Colbert Busch competitive.
1) She'll have the money: The reason the minority party rarely competes for such districts is because they are bad investments, and donors would rather send money to more winnable races. For Colbert Busch, though, her brother's celebrity should help her raise the kind of money that makes her a serious candidate.
She's also locking down the support of organized labor and is holding a news conference Saturday with House Minority Whip James Clyburn (D-S.C.), which suggests an endorsement could be forthcoming.
2) It's a special election: The electorate in special elections is notoriously hard to predict and will be far different than it would be on a normal election day. More than any other race, special elections are about enthusiasm.
Look back on history, and it's not hard to find upsets.
* 2011: Republican Bob Turner won an urban New York district that gave Obama 55 percent of the vote in 2008
* 2011: Democrat Kathy Hochul won the most conservative district in New York (52 percent for McCain)
* 2010: Republican Charles Djou won a Hawaii district that gave John Kerry 53 percent and Al Gore 55 percent (it also gave Obama 70 percent, but that was inflated since he was born there)
* 2008: Democrat Travis Childers won a Mississippi district that had gone 62 percent for President George W. Bush in 2004
* 2008: Democrat Don Cazayoux won a Louisiana district that had gone 59 percent for Bush
* 2004: Democrat Stephanie Herseth (now Herseth Sandlin) won South Dakota's at-large district, months before it went 60 percent for Bush
What do basically all of these people have in common? They are no longer in Congress, having eventually succumbed to the nature of their districts. But they were able to win special elections.
Now, you could argue that any of these elections were special cases -- Djou won in a three-way race, both Turner and Hochul won after incumbents from the other party resigned in scandal, etc. -- but the fact is that special elections are almost always special cases.
Which brings us to point No. 3...
3) Mark Sanford: Democrats are drooling over the idea that they would get a shot at a former governor who is tarnished by his affair with a woman in Argentina. And given the crowded GOP field and Sanford's popularity among conservatives, it could happen.
But among the broader electorate, Sanford may not be the GOP's best option. A poll from Democratic automated pollster Public Policy Polling in December showed his favorable rating at just 30 percent statewide, with 53 percent viewing him unfavorably.
Of course, this is the district Sanford represented before he was governor, so voters there might be more forgiving than the rest of the state. He has also built inroads over the years with black voters, who comprise 20 percent of the district.
Sanford said when he launched his campaign that his favorable rating in the district was higher than his unfavorable rating among Republicans, but it's not clear whether that's the case among all voters.
4) Democrats have already come close: Many don't remember that Rep. Henry Brown (R-S.C.) had a close call in the same district in 2008, beating Democrat Linda Ketner just 52-48. Of course, that was a very strong year for Democrats overall.
Ketner was the rare well-financed Democrat in the district, as Colbert Busch is expected to be. In fact, much of the reason she did so well is that she far outspent the incumbent.
Colbert Busch should at least have the funds to compete, and don't under-estimate the power her brother has to help her. If he can help build a movement around her candidacy, it could make things very interesting.