In 2010, it came to light that the Stuxnet computer worm had struck Iran, reaching its Natanz nuclear facility. Stuxnet eliminated about 1,000 centrifuges by making them speed up and then slow down, creating vibrations that destroyed them.

The damage to Iran’s nuclear program was serious; Israeli intelligence updated its assessment from Iran needing a year to achieve breakout to it needing four years.

In July 2020, Iran was hit by a series of explosions, including one at Natanz. Experts estimated that three-quarters of the aboveground centrifuge assembly facility was destroyed. Iran’s nuclear program was set back by a year or two.

And this week, before Iran was able to recoup the damage caused by the explosion in July, and less than a day after Iran launched new, advanced uranium enrichment machines at Natanz, the site’s electric grid and its backup system were destroyed, along with large numbers of centrifuges. The latest attack is estimated to have added nine months to Iran’s breakout time.

There is a pattern of targeting Natanz, which not even moving much of the facility underground post-Stuxnet could break to stop Israel’s long arm from reaching it. That much is clear.

But there are several major differences between the first two Natanz attacks and the one this week, and they indicate that Israel is bringing its shadow war with Iran into the light at a highly sensitive time.

Unlike this week, the US reportedly worked together with Israel on the 2010 and 2020 Natanz attacks.

Stuxnet was reportedly a joint project of the NSA and the IDF’s Unit 8200, which the Obama administration pushed in part to deter Israel from a more direct military attack on Iran and steer Israel toward sabotaging Iran’s nuclear program instead, and was part of the efforts to get Iran to the negotiating table.

The 2020 Natanz explosion was part of a shared US-Israel strategy to roll back Iran’s nuclear program by striking at it, in tandem with the Trump administration’s maximum pressure sanctions campaign against the Islamic Republic.

This time, the White House was quick to distance itself from the damage in Natanz.“The US was not involved in any manner. We have nothing to add on speculation about the causes or the impacts,” White House Press Secretary Jen Psaki said.

Officials in Washington told The Wall Street Journal that they did not know about the attack on Natanz in advance – another clear signal that the US does not want to be tagged as having been involved.

THEN THERE’S the timing of this week’s attack, days after the start of indirect nuclear talks between the US and Iran in Vienna, for their return to the 2015 Joint Comprehensive Plan of Action, which placed limitations on Iran’s nuclear program, which would expire by 2030, in exchange for the gradual lifting of sanctions.

It also took place just as US Secretary of Defense Lloyd Austin was heading to Israel, making him the first member of the Biden cabinet to visit.

On Monday, Iranian Foreign Minister Javad Zarif wrote an angry letter to UN Secretary-General António Guterres, saying it is likely that Israel committed the “grave war crime” of attacking the nuclear facility in order to derail nuclear talks, and warned that “nuclear terrorism” cannot be used as leverage in negotiations.