Who will watch the watchers?

Former baseball great Roger Clemens, a certain hall-of-famer (until recent events, that is) was indicted for lying to Congress when he swore under oath that he had never used performance-enhancing drugs, a charge that has been disputed by his former trainer.

Congress lies to us all the time, but I guess since they do not first swear an oath before speaking to us, there is no one to indict them.