Scepticism about the U.S. allegation of an Iranian plot to assassinate the Saudi ambassador has focused on doubts that high-level Iranian officials would have used someone like used car salesman Monssor Arbabsiar to carry out the mission.
But when the scanty evidence in the FBI account about what Arbabsiar actually proposed is interpreted in the context of Iran's past strategy for deterring external attack, it suggests that Arbabsiar's mission may have been to arrange for surveillance of and contingency plans for targets to be hit in the event that Iran is attacked by the United States or Israel.
Iran is relatively weak in conventional military strength, so it has relied heavily on unconventional means of deterrence by letting it be known that proxies in other countries could retaliate against U.S. and Israeli targets if those countries attacked Iran. The clearest example of that strategy was an Iranian-directed campaign of surveillance of U.S. targets in Saudi Arabia in 1994-95.
The FBI account contains a series of references to operations said to be proposed by Arbabsiar that hint at just such an unconventional deterrent strategy.
The account says Arbabsiar's interest in the first meeting with an undercover Drug Enforcement Administration (DEA) informant included, "among other things, attacking an embassy of Saudi Arabia". That reference makes it clear that the Iranian interest was not in Ambassador Adel al-Jubeir but in a more generic list of targets.
In a footnote, the FBI account says the "missions" discussed would have involved "foreign government facilities associated with Saudi Arabia and with another country", located both in the United States and elsewhere.
There is not a single quote from any of that series of meetings between late June and mid-July in which Arbabsiar explains the nature and purpose of those missions, despite the fact that most, if not all, the meetings would have been recorded by the DEA informant under standard FBI procedure.
That signal omission may have been necessary to conceal the fact that Arbabsiar was proposing surveillance of various targets and contingency plans that would be carried out against the targets only in case of an attack on Iran by the United States, Israel or both.
The account has the DEA informant saying that it would "take the one point five for the Saudi Arabia" and later adds that he would "go ahead and work on Saudi Arabia, get all the information that we can".
The FBI agent who signed the document then says, "I understand this to mean…that the cost…of conducting the assassination would be 1.5 million dollars." But there is no actual evidence in the document that the figure had been discussed in connection with a proposal for the assassination of the Saudi ambassador.
Those allusions to the "the Saudi Arabia" in the context of a discussion of multiple targets involving more than one country's facilities suggests that the figure was for surveillance of and contingency plans for retaliatory attacks against a number of Saudi targets.
By spring 2011, when Arbabsiar was asked to make contact with paramilitary forces in Mexico, according to the FBI account, Iran had reason to believe that the danger of an Israeli attack with U.S. complicity had increased significantly.
In November 2010, The Guardian had published the text of a November 2009 U.S. diplomatic cable released by WikiLeaks revealing that U.S. and Israeli officials had discussed the delivery to Israel of GBU-28 "bunker buster" bombs that would allow an Israeli attack to penetrate underground Iranian nuclear facilities.
U.S. and Israeli officials in the meeting reported in the cable agreed that it would have to be done quietly to avoid any allegations that the U.S. government was helping Israel prepare for an attack on Iran.
Then Vice Chairman of the Joint Chiefs of Staff Gen. James Cartwright conceded to Newsweek that there was concern among military leaders about how the shipment would be perceived by the Iranians.
The decision to identify Saudi targets for attack in the United States and Mexico presumably reflected strong Iranian suspicions that the Saudi government was prepared to allow Israeli planes to use Saudi airspace to attack Iran, as had been reported by the Times of London and Jerusalem Post in June 2010.
A project to hire a Latin American drug cartel to carry out surveillance of a range of Saudi and Israeli facilities and prepare plans for retaliatory attacks if Iran itself were to be attacked would parallel a similar Iranian campaign involving U.S. targets in Saudi Arabia in 1994 and 1995.
By late 1994, the CIA station in Saudi Arabia was reporting that a number of U.S. targets in the country, including military bases and the U.S. consulate in Jeddah, were under surveillance by Iranians and their Saudi Shia allies, as reported in a Senate Intelligence Committee Staff report in September 1996 and other published sources.
It was generally believed within the intelligence community that this surveillance by Iranian allies in Saudi represented a terrorist threat.
But Ron Neumann, then director of the Office Northern Gulf Affairs in the State Department's Bureau of Intelligence and Research, observed at the time that Iranian surveillance of U.S. targets had recurred whenever U.S.-Iran tensions were high, and could be defensive maneuvers on Iran's part to deter an attack rather than signaling an intent to carry out terrorism.
After the Khobar Towers bombing killed 19 U.S. servicemen in eastern Saudi Arabia in June 1996, the United States accused Iran of having ordered the attack, primarily on the ground that it had organised the surveillance of U.S. targets in Saudi Arabia.
In a striking parallel to the reports in recent days of sensitive intelligence linking Iranian government officials to the alleged assassination plot, the Washington Post reported in April 1997 that there was intelligence tying Hani al-Sayegh, a Saudi suspect in the Khobar Towers bombing, to Brigadier General Ahmad Sherifi of Iran's Revolutionary Guard Corps.
The Post story said that intelligence had "persuaded a growing number of officials in Washington and Ryadh of Iran's direct involvement in the (Khobar Towers) attack".
That intelligence consisted of a secretly recorded al-Sayegh phone conversation in Canada about his meeting with Gen. Sherifi two years before the bombing.
When al-Sayegh was interviewed by Assistant Attorney General Eric Dubelier in May 1997 in Ottawa, Canada, he admitted to having participated in the videotaping of another U.S. airbase in Saudi Arabia as part of a surveillance programme initiated and directed by Sherifi.
But the FBI record of that interview, to which this writer was given access in 2009, shows that al-Sayegh stated very clearly to Dubelier that the surveillance work for the Iranians was not to prepare for one or more terrorist attacks but to identify potential targets for retaliation in the event of an attack on Iran.
When Dubelier later asked him a question which ignored that distinction, al-Sayegh repeated that it was not to prepare for a terrorist bombing.
Thirteen Saudis, including al Sayegh, were indicted in 2001 for carrying out the Khobar bombing, based entirely on alleged confessions by Shi'a activists detained – and presumably tortured – by the Saudis. The indictment blamed Iran for directing the bombing, charging that the defendants had "reported their surveillance activities to Iranian officials and were supported and directed in those activities by Iranian officials".
The 1994-95 Iranian effort in Saudi Arabia, which was apparently not expected to be kept secret from U.S. intelligence, suggests that Iranian officials may have been aiming for a similar effect in seeking a Mexican drug cartel to do surveillance and contingency planning on Saudi and Israeli targets.
Gareth Porter is an investigative historian and journalist specialising in U.S. national security policy. The paperback edition of his latest book, "Perils of Dominance: Imbalance of Power and the Road to War in Vietnam", was published in 2006.