The other thing happening on 6/28. Holder's contempt vote.

Looking up on Wackypedia, it says that the US Attorney has to prosecute anyone found in contempt of Congress. Is that accurate and if so then how can the House allow itself to be made impotent if the US Attorney refuses to prosecute their boss?

Well, that’s what the Office of the Independent Counsel is for. Patrick Fitzgerald resigned in May, but presumably the new guy will prosecute if he feels it’s appropriate.