The political fates are indeed fickle. The sinking of Princess Caroline’s senate nomination has resulted in the appointment of a relative unknown: Rep. Kirsten Gillibrand, an upstate New York Democrat.

Gillibrand is an attractive young politician who, in order to appeal to centrists in her largely Republican district, has earned the support of the National Rifle Association with her pro-Second Amendment stand. That means, unless she changes her tune on that issue, she will still face opposition from downstate liberals such as Rep. Carolyn McCarthy, whose entire political career has been based on her opposition to guns. McCarthy, whose husband was killed in a mad rampage by a gunman on the Long Island Railroad, has already said she will challenge Gillibrand in a primary next year.

If that is indeed the primary match up in 2010, then it will be interesting to see whether New York liberal feminists give Gillibrand (who was blasted by Moveon.org for voting for funding the Iraq war) the Sarah Palin treatment simply because of that NRA endorsement. (Will some of them say she’s “masquerading” as a woman?) Yet I think Gov. David Patterson’s political instincts in this case are pretty good. Gillibrand will not only balance the ticket for New York Dems next year, she may be a formidable candidate in her own right.

But more than that, I’m reflecting on how the course of history and politics can be altered by a single incident.

In late October 2006, Kirsten Gillibrand was just a likable well-funded Democrat running for Congress in a Republican district. Given the Democratic tide that was running high that fall, she wasn’t considered a sacrificial lamb. But neither was she given that much of a chance to beat incumbent John E. Sweeney who was sitting on a fat double-digit lead with time running out.

I met the Congressman that October while he was fund-raising in Philadelphia. At the time, the idea that he might be in danger was the furthest thing from his mind. Instead, he speculated about changes in the Republican House leadership and he clearly anticipated having more influence in the next term.

But then something unexpected happened. The Albany Times-Union published a report about police being summoned to Sweeney’s home in December 2005. The report claimed he had grabbed his wife’s neck and pushed her around the house. He was reported to have scratches on his face. The couple denied the charges and said the report was a fake that was leaked to the press by Gillibrand’s campaign. But they never produced a credible alternative version of the incident.

The Times-Union report turned the election around on a dime. On Nov. 7, 2006 Gillibrand defeated Sweeney, who was branded a wife abuser and a drunk, 53-47 percent. He became just another statistic in the Democratic sweep.

Since then, he has been arrested for drunk driving and he and his wife have divorced. Sweeney, a rising conservative Republican star with working-class roots (his father was the head of a shirt-cutters’ union local in Troy, N.Y.) was toast and Gillibrand’s career was launched.

Yet but for that leaked report, Gillibrand would not be about to sit in the United States Senate, a perch from which she may not be evicted for many years. Such are the ways of politics in which careers may be made or unmade in an instant. The fates are indeed fickle.