In the Syrian civil war, Iranian and Russian forces have fought side by side to keep Bashar al-Assad in power. But cooperation between Moscow and Tehran goes back much further, explains Oved Lobel:

[T]he Islamist regime has maintained a deep warmth for Russia, especially after 1988. The Soviet leader Mikhail Gorbachev was the only foreign leader ever to receive a personal letter from Ayatollah Ruhollah Khomeini (in 1989) urging him to consider Islam an alternative given the imminent collapse of Communism. . . . While the current relationship is a strategic alliance, the Soviet-Khomeini relationship was more akin to the Russo-Turkish alliance of today, in which their highest mutual priority—the destruction of U.S. influence—allowed them to compartmentalize irreconcilable ideological and geopolitical differences.

The most extreme example of this is Afghanistan, where Khomeini and Moscow came to an arrangement whereby Tehran could replicate its Islamic theocracy in Hazarajat, the area predominantly populated by the Hazara Shiite minority, while the Soviets shored up their Communist state in the rest of Afghanistan. . . . Following the sudden rise of the Taliban, Russia and Iran allied against them and backed the Northern Alliance. . . . But, following the U.S.-led invasion in 2001, the two countries collaborated in supporting the Taliban.

Since Vladimir Putin took the helm at the Kremlin, the relationship between the two has only grown stronger:

The clearest demonstration of the Russo-Iranian alliance was their joint intervention in Syria to preserve Bashar al-Assad’s regime, but their anti-U.S. alliance spans the globe. For instance, when the Palestine Liberation Organization (PLO) sought Iranian support during the second intifada, it went to Moscow to connect with the Islamic Revolutionary Guard Corp, resulting in the 2002 Karine A affair, when the Palestinian Authority tried to smuggle 50 tons of Iranian-supplied weapons into Gaza in flagrant violation of the Oslo Accords.

Early Friday morning, Israel attacked military installations near the Iranian cities of Isfahan and nearby Natanz, the latter being one of the hubs of the country’s nuclear program. Jerusalem is not taking credit for the attack, and none of the details are too certain, but it seems that the attack involved multiple drones, likely launched from within Iran, as well as one or more missiles fired from Syrian or Iraqi airspace. Strikes on Syrian radar systems shortly beforehand probably helped make the attack possible, and there were reportedly strikes on Iraq as well.

Iran itself is downplaying the attack, but the S-300 air-defense batteries in Isfahan appear to have been destroyed or damaged. This is a sophisticated Russian-made system positioned to protect the Natanz nuclear installation. In other words, Israel has demonstrated that Iran’s best technology can’t protect the country’s skies from the IDF. As Yossi Kuperwasser puts it, the attack, combined with the response to the assault on April 13,

clarified to the Iranians that whereas we [Israelis] are not as vulnerable as they thought, they are more vulnerable than they thought. They have difficulty hitting us, but we have no difficulty hitting them.

Nobody knows exactly how the operation was carried out. . . . It is good that a question mark hovers over . . . what exactly Israel did. Let’s keep them wondering. It is good for deniability and good for keeping the enemy uncertain.

The fact that we chose targets that were in the vicinity of a major nuclear facility but were linked to the Iranian missile and air forces was a good message. It communicated that we can reach other targets as well but, as we don’t want escalation, we chose targets nearby that were involved in the attack against Israel. I think it sends the message that if we want to, we can send a stronger message. Israel is not seeking escalation at the moment.