The latest report on Iran’s nuclear program from the International Atomic Energy Agency gives ample ammunition to Israeli leaders who argue that they need to bomb now. The report confirms what we have long understood, that Iran is working to build a nuclear weapons capability.

But that’s all. The report doesn’t change the calculus about whether Israeli airstrikes would be the best way to stop Iran’s nuclear weapons effort, and it doesn’t say Iran is building a weapon.

The IAEA’s latest update makes four important things clear. First, that Iran has recently been putting less energy into developing its main uranium enrichment facility at Natanz, and a lot more into expanding production at the hardened bunker at Fordow, near the holy city of Qom.

Second, that the pace at which Iran is producing uranium enriched to 20 percent picked up sharply in February and has continued at that pace -- the report has a handy graph showing that trend. Uranium enriched to about 3.5 percent is used for civilian power plants. Iran says it needs the 20 percent fuel for a medical reactor. But from that stage it’s a lot quicker to enrich to weapons grade, which is about 90 percent.

Both changes coincide with the period in which Israel has been threatening to bomb Iran. It’s hard to determine which is the chicken and which the egg: Israel’s threats or Iran’s dash to build a bombproof production line.

Third, that since the IAEA first demanded access to a military site called Parchin in January, Iran has kept out the inspectors, stalled on negotiations and suddenly begun razing and apparently cleaning the site. The Vienna-based agency was given intelligence that an explosive containment vessel was constructed at the site to develop a detonator for a nuclear warhead. They want to find out if it’s true.

Ayatollah Ali Khamenei on Friday repeated his insistence that Iran is not pursuing nuclear weapons, and that to do so would be “a sin.” So, why the reluctance to admit inspectors to Parchin?

Finally, the report says that IAEA monitoring suggests none of Iran’s enriched uranium stocks appear to have been diverted. Just less than half of the 20 percent enriched uranium Iran has produced so far (the total to August stands at 189.4 kilograms, or 417.6 pounds) is been being used to make plates for the medical reactor. That leaves a stockpile of about 90 kilograms. It takes roughly 175 kilograms to make a bomb. Iran produced about 45 kilograms of the fuel since May, so at that rate, assuming no more is used for the medical reactor, Iran could have enough 20 percent uranium for a bomb by next spring. Iran already has enough lower enriched uranium, though using that stock would be a longer route.

Israeli leaders can’t be sanguine about a nuclear program in the hands of a despotic regime that doesn’t believe Israel should exist. It’s also true that much remains unknown about Iran’s nuclear program -- including other facilities. But then again, if their existence is unknown, they can hardly be targeted with bombs.

Apart from the U.S. electoral calendar, these are probably some of the reasons President Barack Obama’s administration insists there is still more time to pressure Iran into compliance using economic sanctions that only started to bite in July.

Nor does the latest IAEA report change any of the calculations we have mentioned before about the uncertain wisdom of airstrikes conducted by Israel alone. As General Martin Dempsey, chairman of the Joint Chiefs of Staff, said Thursday, these would delay but not stop the Iranian program. Also, the repercussions of an Israeli attack are impossible to predict, and any gain from a delay would probably be lost to an all-out rush by Iran to weaponize after it ejects IAEA monitoring. An Israeli attack without international backing could also help Iran by unraveling sanctions.

None of that means Israel won’t act. If anything, Dempsey’s comment Thursday that he doesn’t “want to be complicit” if Israel chooses to strike suggests he thinks the decision could be close. That may be, but the latest IAEA report, as worrying as it is, does not amount to a trigger. The timing of an Israeli attack would remain political, linked to U.S. presidential elections, and that would be a mistake.

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