The documents suggest that three of the operatives represented themselves as employees of a company called "Coachmen Enterprises" in Washington, D.C. A search of public directories and business records turned up no listing for such a firm.
The vast majority of the agency's overseas officers are under what is known as "official cover," which means they are posing as employees of another government agency. The State Department allows hundreds of its positions in embassies around the world to be occupied by CIA officers representing themselves as diplomats.
A more rare and dangerous job category is "nonofficial cover" - or NOC [pronounced "knock"] - in which CIA officers pose as employees of international corporations, as scientists or as members of other professions. Such covers tend to provide a plausible reason to work long periods overseas and come in contact with foreign nationals the agency wants to recruit.
Plame worked under official cover early in her career but moved to nonofficial, commercial cover during the 1990s, maintaining that status even after she returned from overseas to work at CIA headquarters. Federal election records show that in 1999 she listed as her employer a Boston firm named Brewster-Jennings & Associates, which former agency officials acknowledge was a front company.
NOCs are known for taking extreme risks as part of their work. If caught by a foreign intelligence service, they have no diplomatic immunity to protect them from prosecution under their host country's laws.
Often, even close relatives have to be shielded from the truth. One former NOC said it was particularly traumatic to inform his son, when the boy was in his mid-teens, that his father had been misleading him for years about his true line of work.
"He was pretty stunned," the former NOC said. "He was also disappointed that no, I didn't carry a gun, didn't get to meet pretty enemy spies and that my cell phone was just a cell phone."
Plame's husband, former U.S. Ambassador Joseph C. Wilson IV, said the two met at a diplomatic party in 1997.
"But I didn't know what she did until we were well along in our courtship," he said, adding that her public outing continues to ripple through her private life. "People she has known for upwards of 20 years have all sort of had to go through this period of adjusting to who is the real Valerie Wilson."
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