I’m asking earnestly. After thinking about it for a full day, I can’t come up with a theory. To be clear, I don’t doubt the DOJ’s account: Read Andy McCarthy on why 10/11 Truthers are goofy to think so many Justice Department personnel would be party to a trumped-up case with explosive geopolitical implications. They apparently have hard evidence, including a wire transfer of $100,000 and phone calls from the lead suspect to an alleged Quds Force member in Iran. But that doesn’t answer the questions of why Iran would do it, why they’d do it now, and why they’d do it here. In fact, even the regime’s archenemies in the Iranian dissident community can’t answer those questions:

As Iranians struggled Wednesday to comprehend an alleged plot to assassinate the Saudi ambassador to Washington, analysts here agreed that even if U.S. charges of official Iranian involvement were true, President Mahmoud Ahmadinejad and his government likely had nothing to do with the scheme…

Amid new levels of infighting within Iran’s opaque leadership, Ahmadinejad at present wields no influence over the country’s two main intelligence and security organizations: the Ministry of Intelligence and the Revolutionary Guard Corps. They are firmly under the control of Iran’s supreme leader, Ayatollah Ali Khamenei.

Even against the backdrop of this power struggle, Iranian dissidents and analysts are hard-pressed to come up with reasons for any of Iran’s leaders to undertake such a risky plot. Even if carried out successfully, it probably would have been quickly blamed on Iran, the analysts noted.

Right. If Iran knew that it would have been found out and was intent on committing an act of war on the U.S. and Saudi Arabia anyway, why not do something closer to home where their odds of success are much better? They could have tried to assassinate the Saudi ambassador in any number of Middle Eastern countries where the Quds Force might more easily infiltrate. They could have targeted Robert Ford, the U.S. ambassador to Syria, who’s been making trouble for their pal Assad by showing solidarity with local protesters. They could have plotted some sort of spectacular attack against U.S. troops in Iraq and/or Afghanistan, either large scale a la the 1983 Beirut barracks bombings or smaller scale a la the kidnappings and murders of five American soldiers/a> in Karbala four years ago. The Quds Force is Iran’s A-team, equivalent to the Mossad in Israel. As Robert Baer, a former CIA analyst, told WaPo, “If they wanted to come after you, you’d be dead already.” And yet, their big idea for striking a blow against the Great Satan and its Wahhabist puppet in Riyadh was to … hook a used-car salesman from Corpus Christi up with an alleged member of a Mexican drug cartel? Seriously?

Speaking of which, what would the cartel get out of this arrangement except a bit of cash that it doesn’t need and a lot lot lot of new scrutiny from the world’s greatest military power? Shouldn’t Iran have known something was fishy when the supposed cartel member expressed interest in the plot? Time wonders:

One of my TIME colleagues in Mexico, Ioan Grillo, whose book, El Narco: Inside Mexico’s Criminal Insurgency, is being published this month, agrees. “For the Zetas, political murder is done concretely to protect their own business interests inside Mexico,” Grillo told me today. “It’s just not their modus operandi to carry out political murders in the U.S.”

Had Arbabsiar actually been dealing with the Zetas – and not a U.S. Drug Enforcement Administration informant who posed as a Zeta operative – they probably would have conveyed that reality to him fairly quickly. And they would have likely dismissed the $1.5 million that Arbabsiar allegedly offered the D.E.A. informant. Ditto for the opium the Iranians allegedly threw into the deal. The Zetas, after all, are part of a Mexican drug-trafficking, kidnapping and extortion industry that rakes in as much as $40 billion a year. To risk that kind of cash flow by carrying out a five-alarm international hit for a million and a half bucks seems a non-starter. It also seems an organization like the Iranian Revolutionary Guard, for whom the Justice Department says Arbabsiar may have been working, should know better. Arbabsiar, who lives near Mexico in Corpus Christi, Texas, certainly should have been wiser.

Mafias like the Zetas don’t like to draw attention to themselves for business reasons. Iran, which has some experience with mafia tactics, should have figured that out before proposing a bomb plot in America’s capital targeting a hugely influential diplomat. In fact, read this Danger Room post for an overview of just how bizarrely amateurish the whole operation was, right down to the kitschy euphemisms used for executing someone. Here’s Robert Baer again, writing in Time and trying to make sense of it all:

In its 30-year history of attacking the West, the Quds Force went out of its way never to be caught with a smoking gun in hand. It always used well-vetted proxies, invariably Muslim believers devoted to Khomeini’s revolution. And when the operation was particularly sensitive, they gave the job to Lebanon’s militant Shi’ite Hizballah, organization the Iranians themselves had founded and which has an unsurpassed record in political murder. Hizballah has cells all over the world, including in the United States. But the point of it all was that if caught — and they were, more than once — Iran still enjoyed plausible deniability, a commodity in this business worth its weight in gold. So, if this plot was genuine, why didn’t the Iranians use tried and tested Hizballah networks and keep Iranian nationals, much less unknown Mexican narcos, out of it?

The possible explanations are disturbing as the plot itself. One would be that the Iranian regime has lost control of the IRGC. In that scenario, the convoluted internal political calculus of Iran’s internal power struggles would prompt the faction the plot to have Iranian fingerprints all over this, in order to provoke a confrontation with Washington — in their minds, such a confrontation would be the only way to reunify Iranians behind Khomeini’s revolution.

Another possibility is that this is the work of the Iranian opposition, presumably intending to frame the regime, and draw the United States into conflict that would bring down the mullahs. The Iranian opposition group Mujahedeen e-Khalq, which remains on the U.S. list of international terror organizations despite a strenuous lobbying effort to get itself delisted, is perfectly capable of pulling something like this off.

I don’t know about the second theory but the first makes no sense to me since a Quds Force operation, whether or not authorized by the regime, still should have been more professional than this. If they’re looking to goad America into war for whatever political reason, a successful operation that blew up a few ambassadors/buildings would have gone a lot further than this failed attempt has. As it is, U.S. officials say that our retaliation will consist of isolating Iran globally with new sanctions, blah blah blah. Obama couldn’t have gotten away with something that low key if blood had actually been spilled, so if the IRGC really was intent on starting a war, they did an awfully lame job of it. One other possibility that’s sure to be popular with Obama’s critics is that Iran did this simply to show how vulnerable America is under Obama and to test his mettle by daring him to respond to an act of war in kind, knowing that he’d settle for some soft diplomatic countermeasure instead. The problem with that theory is that The One is a big fan of covert operations himself and, as we know from the Bin Laden raid and the Awlaki strike, is perfectly willing to use special forces and the CIA against leaders of terrorist regimes. He won’t order a bombing run on Tehran but he might very well target higher-ups in the regime and/or the IRGC for revenge. And again, Iran would, or should, know that, which makes the price of ordering this terror plot potentially very, very high for the people who ordered it. All the more reason not to have done it. And yet, according to the DOJ, they did. Why?