The alleged Iranian plot to kill Saudi Ambassador to the United States Adel al-Jubeir on U.S. soil has been dismissed by most commentators as being too far-fetched to be true. Indeed, the plan the U.S. government is accusing the Islamic Revolutionary Guard Corps (IRGC) of coordinating is well outside the organization's traditional sphere. However, Washington's confidence in its accusation is notable, as is the possibility for other, unreleased evidence. If the plot was real, it says much about the Iranian intelligence services' scope, ambitions and capabilities. The IRGC and its elite Quds Force generally have not been responsible for covert operations that do not involve proxy groups or that are far abroad. They mostly stay in the Middle East and South Asia (with a notable appearance in Venezuela in 2010), working to establish ties with insurgent groups they can use as proxies in volatile areas such as Hezbollah in Lebanon, the Jaish-al-Mahdi brigades in Iraq and parts of the Afghan Taliban. Traditionally, the IRGC brings members of these groups to Iran for training. The Quds Force is thought of as a corollary to special operations forces that train foreign militaries and carry out clandestine military operations. Iran's Ministry of Intelligence and Security (MOIS), on the other hand, is generally responsible for operations in Europe and the United States, including a series of assassinations carried out in the 1980s. MOIS is a known operator in the United States and would likely have the resources and experience to carry out a clandestine operation there. This was not the case in the recent incident. Manssor Arbabsiar, the man charged in the plot, allegedly met with an informant for the U.S. Drug Enforcement Administration (DEA) who was posing as a member of a Mexican cartel. This informant never went to Iran, and there is no indication the IRGC is involved in training or arming cartels. It is also odd that the IRGC would use Arbabsiar, a U.S. citizen with both Iranian and U.S. passports who has no apparent connection to the IRGC other than, allegedly, a cousin in the Quds Force. Typically, a trained intelligence officer would be the one to contact a potential proxy group for development, not a new recruit. There also is the question of why al-Jubeir was targeted. It would be much easier for Iranian forces, particularly the IRGC, to kill a Saudi official in the Middle East. Moreover, assassinating al-Jubeir in the United States would likely have serious consequences for Iran — perhaps even in the form of a U.S. military response. The dubiousness of the alleged plot did not stop U.S. officials from blaming it on the IRGC, something they would be unlikely to do without substantial evidence. U.S. President Barack Obama reaffirmed confidence in the evidence against Iran when speaking Oct. 13. In any criminal prosecution in espionage matters, information is often left out for fear of exposing sources and methods. It is possible — though not verifiable — that this is the case in the recent alleged plot. The indictment against Arbabsiar focuses on his confession and the DEA source's activities, but it contains clues about other intelligence the United States could have. The Obama administration reportedly was informed about the plot as far back as June, meaning it had time to assess and confirm its existence. The indictment also never mentions how exactly the informant came in contact with Arbabsiar. If the plot was real, U.S. intelligence officials likely caught onto it by other means than through the informant. The IRGC's ties to the plot could be confirmed with one of the following five pieces of evidence, any of which the United States could have collected with signals intelligence:

• If Arbabsiar's cousin is confirmed as being a member of the Quds Force

• If phone numbers Arbabsiar called after his arrest were connected to the Quds Force

• If the $100,000 Arbabsiar used as a down payment for the attack came from a Quds Force-linked bank

• If other Iranian officers traveled to Mexico to meet the informant

• If the Iranian Embassy in Mexico knew about the operation

The most damning of these would be if Arbabsiar's post-arrest phone calls were traced back to previously identified IRGC offices in Iran. If we assume that at least one of these possible indicators is true, it reveals a few things about Iranian operations. First, it would appear that the IRGC is trying to operate in new territory — though showing a lack of experience operating in the United States and limited capability in such plots. STRATFOR sources also have suggested that a new organization within Iran's intelligence and security services may have been responsible for the plot, which would explain the several mistakes that led to its exposure. One possible connection here would be to two alleged Iranian plots to assassinate dissidents in Los Angeles and London, exposed in the trial of Mohammad Reza Sadeghnia in California and U.S. diplomatic cables released by Wikileaks. Sadeghnia allegedly carried out preoperational surveillance on Jamshid Sharmahd, who made radio broadcasts for the Iranian opposition group Tondar while in Glendora, Calif., and Ali Reza Nourizadeh, who worked for Voice of America in London. Sadeghnia's activities became obvious to his targets, and the fact that he monitored both of them and then returned to Tehran while on bail supports the claims against him. Sadeghnia's profile of an unemployed housepainter from Iran who lived in the United States for many years is very similar to that of Arbabsiar, a used car salesman. Sadeghnia's purported plan to use a third man as a hit man and for the man to employ a used van purchased by Sadeghnia to murder Sharmahd points to a similar lack of sophisticated assassination methodology. While many people believe it possible that U.S. investigators were led on a wild goose chase that they have not yet realized, the investigators' confidence and the possibility for other supporting evidence is notable. It is also quite possible the capabilities of Iran's intelligence services are not nearly as good as previously thought, or at least that some more clumsy organization is involved.