The Iranian regime has a problem, and it's not a velvet revolution or Israel's threat to bomb its nuclear facilities. No, what really keeps the mullahs up at night is the specter of ethnic and sectarian conflict — more attacks like the bombing on Oct. 18 in the remote southeastern province of Sistan-Baluchistan, which killed 42 people, including five senior officers of the Revolutionary Guards Corps. The country's leaders cannot help but worry that the same divisions ripping apart Afghanistan and Pakistan are about to visit them.
Tehran immediately blamed outsiders — the U.S., Great Britain and Pakistan — for Sunday's suicide bombing because it cannot admit that it has its own homegrown Taliban. Whatever Iran says about Jundallah, the ethnic Baluch group that claimed responsibility for the attack, it's an indigenous movement. The body of its financing comes from Baluch expatriates, many in the Gulf, and Islamic charities. Its weapons and explosives are readily available in the mountains that span the border between Iran and Pakistan. (Read "Pakistan: Behind the Waziristan Offensive.")
Pakistani intelligence has indeed had contact with Jundallah over the years, but there's no good evidence that Pakistan created Jundallah from scratch. And there's certainly no evidence that Pakistan ordered the attack. In fact, Pakistani intelligence over the past few years has been arresting Jundallah members and turning them over to Iran.
American intelligence has also had contact with Jundallah. But that contact, as Iran almost certainly knows, was confined to intelligence-gathering on the country; a relationship with Jundallah was never formalized, and contact was sporadic. I've been told that the Bush Administration at one point considered Jundallah as a piece in a covert-action campaign against Iran, but the idea was quickly dropped because Jundallah was judged uncontrollable and too close to al-Qaeda. There was no way to be certain that Jundallah would not throw the bombs we paid for back at us. (See TIME's photo-essay "On the Front Lines in the Battle Against the Taliban.")
For Iran, the hard truth is that ethnic Persians make up only 51% of the population. The rest of the country is a mishmash of ethnic minorities, various religions, Muslim sects and semi-nomadic tribes. None has been entirely happy living under the mullahs' Shi'ite theocracy, especially Iran's Sunni citizens, which make up 9% of the population and include most of the Baluch. Iran's minorities have been susceptible to outside influences, but rarely have they felt strong enough to take on Tehran — which fears that that could change with the chaos at its borders. If, for instance, the U.S. were to suddenly pick up and leave Afghanistan, would the new Taliban government resist backing Jundallah? Or if Pakistan fails to subdue the tribal areas and its own Taliban, would this encourage Jundallah?
Tehran is obviously worried that it has a problem with or without a failure in Pakistan or Afghanistan. The five senior Revolutionary Guards officers killed on Sunday were on their way to a meeting with local tribal chiefs to talk about containing Shi'ite-Sunni violence in their province, and the agenda no doubt included what to do about Jundallah.
In that sense, ironically, Tehran is right that its security really does rest with Pakistan and the U.S. A catastrophic failure on their parts would create a threat that would take Iran many years to overcome.
Baer, a former Middle East CIA field officer, is TIME.com's intelligence columnist and the author of See No Evil and, most recently, The Devil We Know: Dealing with the New Iranian Superpower.