When the White House decided to try a secret diplomatic approach to the Iranians 18 months ago, the man U.S. officials reached out to for help was a conservative consultant with ties to a pro-Israeli organization.

A congressional intelligence source said the Reagan administration turned to consultant Michael Ledeen because he was not a government official and had savvy about the Middle East. He also is a close associate of Robert McFarlane, the former national security adviser who ran the secret operation.

The 45-year-old consultant made several trips to Europe last year for clandestine meetings with Manucher Ghorbanifar, an expatriate Iranian arms supplier who lives on the French Riviera and has close ties to Iranian Prime Minister Mir Hussein Moussavi.