Gonzales's word dance

Thanks to georgia10 over at dKos for highlighting this nugget in the transcript of Gonzales’ testimony, responding to Joe Biden:

“Well, Senator, obviously if Congress were to take some kind of action, and say the president no longer has the authority to engage in electronic surveillance of the enemy, then I think that would put us into the third part of Justice Jackson's three-part test, and that would present a much harder question as to whether or not the president has the authority.”

As georgia10 points out, didn’t Congress already take such action in 1978 with FISA?

Gonzales is trying to get around this by maintaining that FISA has to do with non-enemies like criminals, the mafia, etc. But this is an entirely extralegal reading that has no basis in current law to my knowledge.