WASHINGTON — As the Senate awaits testimony today from the director of central intelligence, Michael Hayden, on CIA interrogation videotapes made in 2002 that have since been destroyed, a blame game is unfolding in the House between two Democratic Party rivals over who knew what and when.

On one side is Speaker Nancy Pelosi, the Democratic leader of California who was briefed on the CIA’s new interrogation methods in 2002 when she was the ranking member of the House Permanent Select Committee on Intelligence. On the other is Rep. Jane Harman, a Democrat of California whom Mrs. Pelosi passed over in 2006 for chairmanship of that committee.

Both lawmakers were briefed about the CIA’s practice of waterboarding, a technique deemed as torture by the American military and the Geneva Conventions, but only Mrs. Harman after her classified briefing sent a letter to the CIA regarding the practice, according to the Washington Post. Specifically, Mrs. Harman, who has asked the CIA to declassify the letter, says she wrote a warning against destroying videotapes.

On Monday, Mrs. Harman took to CNN to trumpet the letter she wrote in 2003. “As a rookie ranking member two weeks in, I was briefed on interrogation matters,” she said. “I was concerned enough about some of the things raised in the briefing that I wrote a highly classified letter, which I have asked be declassified, but it hasn’t been declassified. But Director Hayden basically raised the subject last week, so I can say that in my letter, I say that any planned effort to destroy videotapes would be ill-advised.”

On Sunday, Mrs. Pelosi issued a statement distinguishing between her briefings and those of Mrs. Harman, who she said “was briefed more extensively and advised the techniques had in fact been employed.” She also said she “concurred” with Mrs. Harman’s letter from 2003 that Mrs. Pelosi said protested the new interrogation practices.

Mrs. Harman yesterday met those careful words with an icy politeness. When asked on CNN whether Mrs. Pelosi “dropped the ball” when she was on the intelligence committee in 2002, Mrs. Harman said: “I don’t think so. And she’s speaking for herself. I wasn’t in the meeting she attended. But she says that she has complained about this.”

For Democrats who have made waterboarding of Al Qaeda detainees a major political issue in the run-up to the presidential election year, the disclosures about the interrogation briefings from 2002 and 2003 could be a potential source of embarrassment. At the same time, it opens an old wound between Mrs. Harman and Mrs. Pelosi, but with a twist: Mrs. Pelosi is beloved by the party’s base for her unflinching opposition to the president on war and peace issues, whereas Mrs. Harman is often derided by party’s left-leaning activists.

A California Democratic strategist who knows both women yesterday said Mrs. Pelosi’s decision to deny Mrs. Harman the chairmanship of the intelligence committee was driven more by personality than politics. “Denying Jane Harman the chairmanship of that committee was a curious act, I am not sure it had as much to do with policy but personality,” Garry South said during a telephone interview.

Mr. South pointed out that the difference in their politics is a function of their districts. “Jane Harman came around in 1992 and won a congressional seat, took it away from an incumbent Republican in a district that was designed to tilt towards the Republicans.

It is in the southern part of L.A. County. In order to win that seat, she could not be a flaming San Francisco liberal, she had to be a moderate, there were many defense contractors in that district who made everything from communications satellites to aeronautic parts,” he said.

Mr. South continued: “With all due respect to speaker Pelosi, whose accession to the speakership as the first woman I applaud and respect, you have to be mindful of this fact.”