This morning’s Washington Post features an op-ed on Iran policy by former U.S. Senator Charles (Chuck) Robb and retired U.S. Air Force general Charles (Chuck) Wald. It’s a serious, earnest statement, but also seriously flawed.

The gist of what The Two Chucks have to say is this: we cannot “compel Iran to terminate its nuclear program” unless we threaten to bomb it. Only if we do threaten to bomb it — in addition to imposing sanctions and holding the door open to diplomacy — will we have any real hope of success. This shift to a “triple-track strategy” must be made swiftly, because Iran “could achieve nuclear weapons capability before the end of this year.”

Call it the “Say it with JDAMs“ school of nonproliferation diplomacy. Unfortunately, it overlooks a couple of the key puzzle pieces needed to understand the situation.

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First and most importantly, you can bomb an enrichment facility, but you can’t bomb an enrichment program. (Or not one as well-developed as Iran’s.) It’s not like a reactor, with billions of dollars’ worth of hard-to-replace capital piled up in one spot over the course of several years. Instead, it’s thousands of interchangeable pieces that can be brought together and operated more or less anywhere.

To illustrate the point, here’s an interior view from Iran’s centrifuge facility at Natanz:

Any one of those centrifuges — the tall, silvery tubes in the picture — and the piping connecting them can be replaced in short order.

What’s more, the entire complex could be buried in wreckage, and the centrifuge workshops would simply start sending their products to a different location.

Bomb the workshops — if you are lucky enough to locate them — and new workshops could be set up before very long.

Following this line of reasoning leads you to a realization that Iran’s capacity for precision engineering would have to be bombed somehow. That’s not a problem with a solution.

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Second, Robb and Wald are mistaken about when Iran will achieve “nuclear weapons capability.” The Iranians could start producing highly-enriched uranium for bombs before you go to bed tonight. They could have started years ago, in fact. That they have not done so, as far as anyone knows, renders the art and science of timeline-ology, as Robb and Wald are practicing it, more or less moot.

(It helps to recall that the timelines sometimes discussed by representatives of the Intelligence Community reflect features such as how much time it takes to set up a new clandestine facility like the one at Qom, as opposed to anything special happening at the big showpiece facility at Natanz.)

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Perhaps you’re wondering: So if we can’t bomb their enrichment program, why haven’t the Iranians already started making bomb material? What’s holding them in check?

One possibility is, maybe they’ve decided they don’t want to, or feel they don’t need to.

A second possibility is, they think the price of forging ahead would be too high. The sanctions are bad enough as it is.

A third and related possibility is that they think that the price might involve not just the bombing of an enrichment facility here or an air defense system there, but a much more comprehensive sort of attack, one that would threaten the regime’s grip on power.

Here is where we might start a different sort of conversation about the utility of threats. As Tom Schelling pointed out some decades ago, threats are much more useful for trying to deter action than for trying to compel action. After all, if Iran were to withdraw from the Non-Proliferation Treaty (NPT) or kick out inspectors, then they would have crossed a line, not the other side. It is much easier to justify the use of force in response to a grave provocation than in terms of a technological timeline generated with a spreadsheet somewhere, and subject to a variety of assumptions.

In the meantime, certain advantages accrue to the United States and its allies from not dropping JDAMs. One is that the international community can continue to monitor Iran’s nuclear programs, albeit not as well as it should. To start bombing would probably mean losing that access, since the Iranians would probably respond by leaving the NPT and rebuilding their centrifuge facilities in secret somewhere. In short, the real Iran “nuclear timeline” has to do with leadership decision-making more than technical milestones. Bombing might well accelerate that timeline, not slow it.