How do you slow down Iran's nuclear program without bombing them? You screw up their computers with an extraordinarily sophisticated computer program that attacks only the computers involved in their enrichment operations.

It is not news that Stuxnet has set back the Iranian nuclear program several years (some analysts believe it may be as many as 4 years). What might be news is that we are getting very strong indications that this was a joint Israel-US operation run out of the super secret Israeli nuclear facility at Dimona:

Behind Dimona's barbed wire, the experts say, Israel has spun nuclear centrifuges virtually identical to Iran's at Natanz, where Iranian scientists are struggling to enrich uranium. They say Dimona tested the effectiveness of the Stuxnet computer worm, a destructive program that appears to have wiped out roughly a fifth of Iran's nuclear centrifuges and helped delay, though not destroy, Tehran's ability to make its first nuclear arms.

"To check out the worm, you have to know the machines," said an American expert on nuclear intelligence. "The reason the worm has been effective is that the Israelis tried it out."

Though American and Israeli officials refuse to talk publicly about what goes on at Dimona, the operations there, as well as related efforts in the United States, are among the newest and strongest clues suggesting that the virus was designed as an American-Israeli project to sabotage the Iranian program.

In recent days, the retiring chief of Israel's Mossad intelligence agency, Meir Dagan, and Secretary of State Hillary Rodham Clinton separately announced that they believed Iran's efforts had been set back by several years. Mrs. Clinton cited American-led sanctions, which have hurt Iran's ability to buy components and do business around the world.

The gruff Mr. Dagan, whose organization has been accused by Iran of being behind the deaths of several Iranian scientists, told the Israeli Knesset in recent days that Iran had run into technological difficulties that could delay a bomb until 2015. That represented a sharp reversal from Israel's long-held argument that Iran was on the cusp of success.

This has been a long term project - perhaps begun as long ago as the Clinton administration but certainly predating the current administration. What we do with the time granted us by the success of this remarkable effort matters more than the development of the worm in the first place.

Hat Tip: Ed Lasky