Historically, Tehran has aligned with Christian Armenia over Shiite Muslim, but pro-Western, Azerbaijan. Yet the recent outbreak of fighting between the two former Soviet republics poses a dilemma for neighboring Iran, as members of its large population of ethnic Azeris have been vocally expressing their support for their brethren across the border. Alex Vatanka explains:

Azerbaijan, one of four Shiite Muslim-majority countries in the world (together with Iran, Iraq, and Bahrain), also happens to have close economic, military, and intelligence ties with Israel, Tehran’s regional archfoe. But the popular momentum behind fully siding with Baku has been so great that Tehran has not even allowed Azerbaijan’s close partnership with Israel to get in the way. . . . Simply put, Iran is not in a position to act in opposition to its own Azeri minority.

Also at play in Iran’s calculations will be Turkey, the third-party actor in this conflict that Tehran watches the most intently. Tehran has accused Ankara of fueling the conflict by urging Azerbaijan to . . . attempt to recapture as much of its occupied territory as possible before agreeing to a ceasefire and diplomatic talks. However, while Iran is still tangled up with Turkey in Syria—where Iran supports the regime of Bashar al-Assad while Turkey backs the opposition—Tehran won’t want to escalate tensions over Armenia and Azerbaijan too far.

[Moreover], despite the lingering suspicion between the two powers, Turkey is an important neighbor and trading partner for Iran. Thanks to its isolation, Tehran does not want to see Ankara join its (already long) list of open adversaries. No matter how carefully the Iranians play their cards in this latest conflict in the South Caucasus, the simple reality is that Tehran holds a much weaker hand in the region now than it did in the early 1990s.

While I’ve seen much speculation—some reasonable and well informed, some quite the opposite—about why Jerusalem chose Friday morning to begin its campaign against Iran, the most obvious explanation seems to be the most convincing. First, 60 days had passed since President Trump warned that Tehran had 60 days to reach an agreement with the U.S. over its nuclear program. Second, Israeli intelligence was convinced that Iran was too close to developing nuclear weapons to delay military action any longer. Edward Luttwak explains why Israel was wise to attack:

Iran was adding more and more centrifuges in increasingly vast facilities at enormous expense, which made no sense at all if the aim was to generate energy. . . . It might be hoped that Israel’s own nuclear weapons could deter an Iranian nuclear attack against its own territory. But a nuclear Iran would dominate the entire Middle East, including Egypt, Jordan, the United Arab Emirates, and Bahrain, with which Israel has full diplomatic relations, as well as Saudi Arabia with which Israel hopes to have full relations in the near future.

Luttwak also considers the military feats the IDF and Mossad have accomplished in the past few days:

To reach all [its] targets, Israel had to deal with the range-payload problem that its air force first overcame in 1967, when it destroyed the air forces of three Arab states in a single day. . . . This time, too, impossible solutions were found for the range problem, including the use of 65-year-old airliners converted into tankers (Boeing is years later in delivering its own). To be able to use its short-range F-16s, Israel developed the “Rampage” air-launched missile, which flies upward on a ballistic trajectory, gaining range by gliding down to the target. That should make accuracy impossible—but once again, Israeli developers overcame the odds.