When this story first broke on Tuesday, it sounded very much like a major terror attack against the US had be thwarted. As the story developed, the story became the US thwarted an attempt by Iranians (contracted through a Mexican drug dealer) to attempt an assassination of the Saudi Arabian ambassador to the US. The plot supposedly involved the Iranian Islamic Revolutionary Guards Coprs (Quds Force, an elite unit contained within), which would be like the SEALs or Delta Force plotting an assassination but getting arrested after arriving at the airport. The attempt was amateurish and not indicative of the Quds Force. The question of course is why?
The US and Iranian relations have been strained ever since the Tehran embassy was stormed and American hostages seized in 1979. Fifty-two Americans were held hostage for 444 days. The Shah was deposed and the Ayatollah Khoemeni returned from exile to establish a theocratical government. Prior to these events, Iran was one of the main allies of the United States in the region. To this day, Iran still flies F-14s sold to them by the US. The US was so enamored with Iran that the CIA staged the coup allowing the Shah to assume power.
The 1990s did little to improve US/Iranian relations (remember Reagan was elected in large part because of Carter's inability to get the hostages release). The Bush Administration, hellbent on waging the Global War On Terror (GWOT), saw Iran as part of the axis of evil. Relations became even more strained as the GWOT hunted weapons of mass destruction, Iran's past dabbling with nuclear reactors became a major focus.
President Obama ran on a campaign on bringing the troops home and by implication, end the war on terror. The first signs he was going to keep his promise was when he reduced the troop strength in Iraq...only to immediately increase the troop strength in Afghanistan! Okay, fair enough as the Afghani campaign had been, in the minds of many experts, ignored. But then Secretary Clinton started to make statements about how unacceptable it was that Iran (now being run by Ahmadinejad) was pursuing a policy of acquiring nuclear weapons. Ahmadinejad countered that US imperialism was cause for his country to be concerned and take appropriate measures.
If it seemed a stretch that the US would go to war with Iran, when Odyssey Dawn (the air campaign against Libya's Gaddafi) was launched it seemed more like a prelude to attacking Iran than supporting Libyan rebels (another country who used to a US ally in the 1960s). Syria, which benefits from its relationship with Iran, has been going through its own Arab Spring with Assad worried about his future. Unlike Libya, no air support means the rebels have not had as much success. Syria could be prove to be the catalyst to a much broader conflict between the US and Iran.
The attempted assassination of the Saudi ambassador seems to be either a clumsy attempt by Iran to incite a conflict or the US looking for zebras whenever they hear hoof beats.
U.S. Accusations of Iran Plot Face Skepticism - NYTimes.com