Iran's nuclear program hits the headlines these days, but there is no answer to the crucial question. How far are they from a working nuke?
Everyone who's got Khan's blueprint (which is almost freely available, beside having been presented to the Iranians by its author) can easily build a nuke if he's got enough U-235. With enough reasonably pure U-235 building a nuke is quite easy anyways. So the question is, how long do they need to produce pure-enough U-235 in reasonable multiples of 20kg ?
If they are trying to get there the standard centrifuge-based way, they are at least several years off. They will have to build or obtain thousands of new centrifuges. Then they'll have to operate them for years. It's a complex, costly and very energy intensive operation. Besides, the specifics of the uranium mineral from Iranian mines may require tricky modifications to the standard technology, which may slow down progress substantially, unless they manage to buy better mineral from abroad, which is unlikely. Anyways, even without the latter complication, centrifuge-based uranium enrichment is a large-scale project that cannot be kept secret and is highly vulnerable. There is plenty of time there.
Is that all?
The Iranians claim they have disbanded their laser isotope separation (LIS) project in 2003. LIS is quite high-tech stuff, but it can be implemented as a small-scale operation yielding relevant amounts of U-235 of excellent purity. If you want to hide and are smart enough to master the technology, that's the way to go.
So the key question, as I see it, is now the following. Was the Lashkar Abad LIS pilot facility really dismantled or was it just moved underground?
On the other hand, if, as widely claimed, LIS is really too difficult to be within Iran's technological reach, I surmise that we can sleep peacefully.