"JUST four members of Congress were notified in 2002 when the Central Intelligence Agency’s “enhanced interrogation techniques” program was first approved and carried out, according to documents released by the agency last week."
(snip)
"Each was briefed orally and it was understood that they were not to speak about the program with anyone, including their colleagues on the committees."
(snip)
"as a practical matter, there was very little, if anything, the Gang of Four could have done to affect the Bush administration’s decision on the enhanced interrogation techniques program. To stop it, they needed the whole Congress."

I suppose they figured that if they broke one law they may as well break more. But even worse and more likely is that they just didn't care.