Seymour Hersh reports on US covert actions, aka, "black ops", involving the Iranian terrorist group Mujahideen-e-Khalq (MEK) in Our Men in Iran? New Yorker 04/06/2012:
It was here [a base in Nevada] that the Joint Special Operations Command (JSOC) conducted training, beginning in 2005, for members of the Mujahideen-e-Khalq, a dissident Iranian opposition group known in the West as the M.E.K. The M.E.K. had its beginnings as a Marxist-Islamist student-led group and, in the nineteen-seventies, it was linked to the assassination of six American citizens. It was initially part of the broad-based revolution that led to the 1979 overthrow of the Shah of Iran. But, within a few years, the group was waging a bloody internal war with the ruling clerics, and, in 1997, it was listed as a foreign terrorist organization by the State Department. In 2002, the M.E.K. earned some international credibility by publicly revealing—accurately—that Iran had begun enriching uranium at a secret underground location. Mohamed ElBaradei, who at the time was the director general of the International Atomic Energy Agency, the United Nations' nuclear monitoring agency, told me later that he had been informed that the information was supplied by the Mossad. The M.E.K.'s ties with Western intelligence deepened after the fall of the Iraqi regime in 2003, and JSOC began operating inside Iran in an effort to substantiate the Bush Administration’s fears that Iran was building the bomb at one or more secret underground locations. Funds were covertly passed to a number of dissident organizations, for intelligence collection and, ultimately, for anti-regime terrorist activities. Directly, or indirectly, the M.E.K. ended up with resources like arms and intelligence. Some American-supported covert operations continue in Iran today, according to past and present intelligence officials and military consultants. [my emphasis]
There is a big difference between intelligence operations aimed and getting information and covert action aimed at fomenting violence or activity against a hostile regime or directly committing acts of violence. However romantic an image many people may have of the latter, the risk/return ratio on such actions is very high. And can even constitute acts of war.
The fact that the United States has been involved in actions like training the MEK and possibly in terrorist attacks inside Iran needs to be very much a part of the discussion of US policy toward Iran.
Five Iranian nuclear scientists have been assassinated since 2007. M.E.K. spokesmen have denied any involvement in the killings, but early last month NBC News quoted two senior Obama Administration officials as confirming that the attacks were carried out by M.E.K. units that were financed and trained by Mossad, the Israeli secret service. NBC further quoted the Administration officials as denying any American involvement in the M.E.K. activities. The former senior intelligence official I spoke with seconded the NBC report that the Israelis were working with the M.E.K., adding that the operations benefitted from American intelligence. He said that the targets were not "Einsteins"; "The goal is to affect Iranian psychology and morale," he said, and to "demoralize the whole system—nuclear delivery vehicles, nuclear enrichment facilities, power plants." Attacks have also been carried out on pipelines. He added that the operations are "primarily being done by M.E.K. through liaison with the Israelis, but the United States is now providing the intelligence." An adviser to the special-operations community told me that the links between the United States and M.E.K. activities inside Iran had been long-standing. "Everything being done inside Iran now is being done with surrogates," he said. [my emphasis]
Aside from the advisability, or the lack thereof, for such actions, Glenn Greenwald points out that they are literally illegal. Because MEK is on the official US list of terrorist organizations, and it is specifically illegal to provide money, weapons or training to such groups: Report: U.S. trained terror groupSalon 04/06/2012.