Lance Armstrong has finally fessed up to what everyone already knew, but after a lifetime of angry, vindictive denials of performance enhancing drug use, he's only opened the door to more legal troubles.

The exact details of his confession and his explanation for it will have to wait until a major interview airs later this week. (Oprah Winfrey confirmed this morning on CBS that the entire 2.5-hour interview will be broadcast over two nights, on Thursday and Friday, and that Armstrong was "forthcoming.") However, it's been widely assumed that Armstrong had two goals in mind. One is to lift his lifetime ban from competitive sports given to him by the U.S. Anti-Doping Agency. The other is to settle any remaining lawsuits and avoid further prosecutions. Unfortunately, to accomplish either of those things, he will have to become the person he supposedly reviles the most: a rat. 

Several news outlets are reporting that Armstrong is offering to testify against officials at the International Cycling Union and the owners of his old U.S. Postal Service team, presumably in exchange for some sort of immunity or reduced punishment. When former teammates have leveled accusations or even testified against him in the past, Armstrong routinely painted them as liars and cheats, saying (correctly) that they were admitted drug users simply cutting a deal to save their own skin. Now he's in their shoes and it won't take a very savvy lawyer to use his own words against him.

Not only that, there's an excellent chance that he's already perjured himself once (even though the statute of limitations on one case has passed.) That doesn't exactly make Armstrong the strongest witness for the prosecution.

The other issue is: Who is he supposed to snitch on? When prosecuting organized crime, the lower lever crooks usually testify against their superiors, with prosecutors working their way up the food chain until they get to The Big Boss. The problem for Armstrong is that he is The Big Boss. Yes, he may be able to make cases against other top sporting officials, but the seven-time Tour de France winner was always the big fish that doping officials wanted to bring down. In theory, he could expose the whole sport, but why let him off the hook for an arguably smaller catch?

Then there's actual legal issues his confession has exposed him to. While federal prosecutors have already dropped an investigation into possible drug trafficking and money laundering charges, and he's no longer being pursued by international doping officials for cheating, Armstrong still faces lawsuits from sponsors, media organizations, and numerous friends and employees that he's done battle with over the years. The most significant is a federal whistle-blower lawsuit filed against him by former teammate Floyd Landis. The Wall Street Journal is reporting that Justice Department officials are considering joining the lawsuit in an effort to win back tens of millions of dollars given to his U.S. Postal Service team while he was doping. If they do just that, government lawyers would take over the case on behalf of Landis and give him 30 percent of any damages they recover.

CBS News has already reported that Armstrong is in talks to give back much of that money and possibly testify against the owners of the Postal Service team. Once again, federal officials may indeed cooperate and give him the deal he seeks (and it's unlikely Armstrong would have come forward if some sort of deal wasn't already in place), but it's not clear why they should. The confession allows doping officials and prosecutors to taken everything they want right now. They get his money, his titles, the biggest sports doping prosecution ever, and the right to say "I told you so." 

They don't need his testimony to make their case, and they'd be rewarding a man who lied for over a decade, threatened opponents, and attacked people who were telling the truth. Armstrong was banned for life without doping officials even having to prove their case in court. Now that he's admitted to the crime, should the punishment goes away?

Perhaps Armstrong will actually blow the whole doping story wide open, creating massive ripple effects that clean up the drug problem across the sporting world—maybe even the Olympic movement itself. But he still has a long way to go to meet that burden of proof. Even that might not save his shattered reputation.