WASHINGTON  One of the leading House Democrats on intelligence matters was overheard on telephone calls intercepted by the National Security Agency agreeing to seek lenient treatment from the Bush administration for two pro-Israel lobbyists who were under investigation for espionage, current and former government officials say.

The lawmaker, Representative Jane Harman of California, became the ranking Democrat on the House Intelligence Committee after the 2002 election and had ambitions to be its chairwoman when the party gained control of the House in 2006. One official who has seen transcripts of several wiretapped calls said she appeared to agree to intercede in exchange for help in persuading party leaders to give her the powerful post.

One of the very few members of Congress with broad access to the most sensitive intelligence information, including aspects of the Bush administration’s wiretapping that were disclosed in December 2005, Ms. Harman was inadvertently swept up by N.S.A. eavesdroppers who were listening in on conversations during an investigation, three current or former senior officials said. It is not clear exactly when the wiretaps occurred; they were first reported by Congressional Quarterly on its Web site.

The official with access to the transcripts said someone seeking help for the employees of the American Israel Public Affairs Committee, a prominent pro-Israel lobbying group, was recorded asking Ms. Harman, a longtime supporter of its efforts, to intervene with the Justice Department. She responded, the official recounted, by saying she would have more influence with a White House official she did not identify.