"Just because we're not finding them doesn't mean they're not there," says Major Alayne Conway of the dread Iranian infiltrators. By the same token, of course, maybe the insurgency is being fueled by Martians or Venezuelan space terrorists -- after all, just because we're not finding them doesn't mean they're not there. This is all from Chris Collins' report for McClatchy which makes the evidence sound pretty thin:
Conway said that U.S.-led forces have not caught any of the Iranians, but she said military intelligence and recently discovered caches of weapons with Iranian markings on them indicate that the Iranians are there.
Lynch's assertion is the latest in a series of accusations leveled by military officials against Iran. They have warned that Iraq's neighbor is actively supplying Shiite insurgents - specifically, the Mahdi Army - with deadly weapons that have killed dozens of U.S. soldiers.
So there you have it. Given the vagaries of the small arms market and the fact that Iran is conveniently located next to Iraq, it's hard to say what this is supposed to mean. The core point, however, remains that even if the full bill of particulars against Iran is true and they're the primary source for EFPs and Mahdi Army weapons more generally (this last is plausible -- their guns come from somewhere) it's not at all clear why you'd think escalating the conflict with Iran would be the preferred solution. The US has already thrown way, way, way more of our assets into Iraq than has Iran -- any escalation we undertake can be responded to and not necessarily to our advantage.
Rationally, the Iranian government can no more be indifferent to events in Iraq than we could be to a massive Iranian invasion force in the middle of a civil war in Mexico. We can either escalate to full-scale war with Iran, or we can reach some kind of agreement that takes care of both sides' core interests.