Why would the US government go after Bitcoin? Indicting the directors of e-gold was one of the greatest accomplishments of Bush's Department of Justice and hopefully we will never again see such an insane justice department.

The government generally frowns on alternative modes of currency that aren't in their power. They really aren't going to like a form that is essentially untraceable. Either one of those would be enough for the government to be unhappy with. I'm also pretty sure that e-gold was very low down on Justice's priority list during Bush, and it doesn't take an "insane justice department" just a government that wants to be able to track money, control the size of the money supply, and be able to effectively tax.

Also, there is no US entity to even prosecute, just an IRC channel to gain control of. Some cyberpunk future where the world governments are trying to hack Bitcoin is almost more likely than any of the users being sued for things for things other than committing crimes while happening to be using Bitcoin at the same time.

When confronted with a problem, do you first try to use your existing skills and powers to solve a problem or others? Now, what ability do federal prosecutors have that most of the world doesn't? (Hint:The correct answer is not "an army of skilled of hackers".)