Soviet Show Trial in America

Regarding Roger Clemens testifying before Congress, Lew Rockwell writes:

Of course, the inquisitors are actually getting both men for the non-crime of allegedly fibbing to a fed. I know that poor Clemens can't do it, but when one of the creeps kept reminding him he was "under oath," I wanted him to respond, "Yes, unlike you."

Which does bring up a good point, cops and prosecuters lie all the time to get indictments, to "catch" people for crimes, or non-crimes (see the Duke Lacrosse Players). But what consequences do "the authorities" face when they are the ones engaged in criminal acts? In the case of the Duke Lacrosse DA Mike Nifong (the most egregious and publicized example), I haven't seen criminal charges filed yet. And it's unlikely that we ever will.