According to the terms of the 2015 agreement, the Islamic Republic was required to remove the core, or calandria, of its Arak nuclear reactor and fill it with cement, thus preventing its further use. It would then be allowed to rebuild and redesign the reactor so that it could be used for research but could not easily produce weapons-grade plutonium. But in recent public statements, Ali Akbar Salehi, the head of the Iranian Atomic Energy Organization, stated that these requirements had not been fulfilled. Michael Segall writes:

Salehi suggested that Iran would continue to “discover and mine” uranium . . . and continue with its activities at the heavy-water reactor in Arak. Iran has purchased new equipment for the facility and did not even fill in the core of the reactor with cement in January 2016 in accordance with the nuclear deal, because “if we had done that, there would not be a reactor.” . . .

On January 16, 2016, the International Atomic Energy Agency’s Board of Governors released a report, . . . which confirmed that Iran had removed and “rendered inoperable” the Arak facility’s calandria. [But] during an interview [on Iranian television] on January 22, 2019, Salehi criticized claims by the conservative camp that Iran had completely sealed the core of the reactor. He claimed that images published [of the sealed reactor in 2016] were photoshopped, and Iran was never required by the agreement to seal the core of the reactor with concrete. . . . Salehi emphasized throughout the interview [the Iranian nuclear program’s] progress [despite] the implementation of the nuclear agreement. . . .

Salehi’s words follow his statement on January 15, 2019, that Iran is capable of increasing its percentage of uranium enrichment to 20 percent within three or four days.

Surveying news websites and social media on Sunday morning, I immediately found some intelligent and well-informed observers arguing that Iran deliberately warned the U.S. of its pending assault on Israel, and calibrated it so that there would be few casualties and minimal destructiveness, thus hoping to avoid major retaliation. In other words, this massive barrage was a face-saving gesture by the ayatollahs. Others disagreed. Brian Carter and Frederick W. Kagan put the issue to rest:

The Iranian April 13 missile-drone attack on Israel was very likely intended to cause significant damage below the threshold that would trigger a massive Israeli response. The attack was designed to succeed, not to fail. The strike package was modeled on those the Russians have used repeatedly against Ukraine to great effect. The attack caused more limited damage than intended likely because the Iranians underestimated the tremendous advantages Israel has in defending against such strikes compared with Ukraine.

But that isn’t to say that Tehran achieved nothing:

The lessons that Iran will draw from this attack will allow it to build more successful strike packages in the future. The attack probably helped Iran identify the relative strengths and weaknesses of the Israeli air-defense system. Iran will likely also share the lessons it learned in this attack with Russia.

Iran’s ability to penetrate Israeli air defenses with even a small number of large ballistic missiles presents serious security concerns for Israel. The only Iranian missiles that got through hit an Israeli military base, limiting the damage, but a future strike in which several ballistic missiles penetrate Israeli air defenses and hit Tel Aviv or Haifa could cause significant civilian casualties and damage to civilian infrastructure, including ports and energy. . . . Israel and its partners should not emerge from this successful defense with any sense of complacency.