Appearing on "Fox News Sunday," Feinstein -- who chairs the Senate Intelligence Committee -- confirmed she had been told by CIA Director Leon Panetta about an intelligence gathering program the CIA ran for eight years, that was so secret Panetta wasn't told about it until four months after he took office.
Feinstein said Congress "should have been briefed before the commencement of this kind of sensitive program."
"Director Panetta did brief us two weeks ago … said he had just learned about the program, described it to us, indicated that he had canceled it and, as had been reported, did tell us that he was told that )former Vice President Dick Cheney) had ordered that the program not be briefed to the Congress."
Feinstein said the need for secrecy is understandable but "the law is very clear" and "I think you weaken your case when you go outside of the law."
Appearing on the same program, Sen. John Cornyn, R-Texas, said disclosure of the secret program and Cheney's purported role in keeping knowledge of it from Congress might be motivated by partisan politics.
"Well … this, of course, comes on the heels of a statement -- unproven, by the way -- of Speaker (Nancy) Pelosi that the CIA had lied to her about enhanced interrogation techniques, and this looks to me suspiciously like an attempt to provide political cover to her and others," Cornyn said.
Speaking of a series of reports issued last week by five inspectors general, Feinstein said she understands why Attorney General Eric Holder is reportedly considering investigating possible CIA involvement in torture of suspected terrorists.
"Well, I don't know whether Sen. Cornyn has read those inspector general reports, but I have, and they are chilling," she said.