WASHINGTON  Duane R. Clarridge parted company with the Central Intelligence Agency more than two decades ago, but from poolside at his home near San Diego, he still runs a network of spies.

Over the past two years, he has fielded operatives in the mountains of Pakistan and the desert badlands of Afghanistan. Since the United States military cut off his funding in May, he has relied on like-minded private donors to pay his agents to continue gathering information about militant fighters, Taliban leaders and the secrets of Kabul’s ruling class.

Hatching schemes that are something of a cross between a Graham Greene novel and Mad Magazine’s “Spy vs. Spy,” Mr. Clarridge has sought to discredit Ahmed Wali Karzai, the Kandahar power broker who has long been on the C.I.A. payroll, and planned to set spies on his half brother, the Afghan president, Hamid Karzai, in hopes of collecting beard trimmings or other DNA samples that might prove Mr. Clarridge’s suspicions that the Afghan leader was a heroin addict, associates say.

Mr. Clarridge, 78, who was indicted on charges of lying to Congress in the Iran-contra scandal and later pardoned, is described by those who have worked with him as driven by the conviction that Washington is bloated with bureaucrats and lawyers who impede American troops in fighting adversaries and that leaders are overly reliant on mercurial allies.