The FERC
The Federal Energy Regulatory Commission is supposed to regulate the interstate energy business, and it's supposed to act as a watchdog to prevent the kind of ripoff California suffered. Contracts for supplying energy interstate are specifically under their supervision.
But the moment Bush, Cheney, and the energy industry took the White House, the FERC went on vacation. California finally had to sue, and with the courts grabbing the FERCers by the scruff of the neck and forcing them to do their jobs, they quickly came up with violations to the tune of over a $billion. A token amount, but enough to provide political cover for the Bush-Energy Administration.