In short via Jeff Stein at CQ politics:
1. Congressman Jane Harman (D - CA) told a suspected Israeli agent that she would lobby the Justice Department to reduce espionage-related charges against two officials of AIPAC, the powerful pro-Israel lobby.
2. This was known because of an NSA Wiretap.
3. The suspected Israeli agent then promised to lobby Nancy Pelosi to make Harman chair of the House Intelligence Committee after the 2006 elections (she wasn't).
4. There were some reports of this influence peddling in 2006, but it was dropped for a “lack of evidence” by Alberto R. Gonzales, who intervened to stop the investigation.
5. Gonzales intervened because he wanted Harman to defend the administration’s warrantless wiretapping program, which was about break in The New York Times.
6. And she promptly went out and defended it.