From the Cable comes the account of Mari Carmen Aponte, President Obama's nominee to be ambassador to El Salvador--who also happens to have dated a Cuban-American who the Federal Bureau of Investigation at one point thought might have been some sort of double agent. The relationship, and her talks with the FBI about it, scuttled another nomination in 1998.
Now, on one hand, I really believe people shouldn't be locked out of government jobs for things they did when they were young. If government is ultimately full of people who spent their whole lives in sanitized preparation to go through a confirmation process, then government is going to have a whole lot less strategic capacity than if it has folks who have had diverse life experiences, who have made mistakes, and who have grown from them.
On the other hand, Aponte was fully grown-up when the relationship happened. It's not like she was 18, and fell for a guy way more sophisticated than she did who concealed a lot of things from her. So I can understand questioning her judgement, especially since she socialized with some of the folks who were involved in Cuba efforts with him. But if the FBI has given her a clean bill of health, intelligence-wise, I think a judgement debate is about as far as it can go. She might have chosen a bad person to date, but it's probably not fair to treat her as if she's actually compromised.