Since Donald Trump began applying increased economic pressure on Tehran, critics have argued that, without the support of U.S. allies, these measures will prove ineffective or even backfire. After demonstrating that events have proved most objections wrong, John Hannah moves to the question of whether economic warfare can really succeed in keeping Iran from obtaining nuclear weapons:

President Trump’s maximum-pressure strategy may still seem ambitious, but hardly fantastical. Indeed, at least as far as constraining the regime’s resources is concerned, it’s impossible at this point to argue that the policy is not making progress. The regime is systematically being denied billions of dollars that it heretofore was using both to subsidize its domestic stability and to finance its imperial ambitions. As its revenues continue to shrink, choices about resource allocation have grown increasingly difficult.

While the tightening squeeze may not yet have translated into a noticeable retrenchment of its regional activities, the regime’s day of reckoning is almost certainly coming as the specter of financial insolvency looms on the horizon. It is lashing out now [with its recent attacks on the oil trade] precisely because it feels the walls closing in and hopes to force the United States to back off before its situation becomes much more perilous. Iran’s decision to escalate is, paradoxically, a sign that the maximum-pressure campaign may be working, not failing. . . .

The chances that the European Union or other world powers will be capable of circumventing the U.S. sanctions wall, now or in the foreseeable future, are slim. What remains in serious doubt, however, is whether Trump’s maximum-pressure policy can be translated into strategic outcomes—by significantly eroding the regime’s ability to project power and forcing it back to the negotiating table to work out a new agreement that substantially improves on the 2015 deal. All, of course, while containing Iranian escalation and avoiding a costly war.

Trump’s critics are betting that it can’t be done. They could eventually turn out to be right. But for now, that judgment remains premature. The ultimate success or failure of Trump’s Iran policy, as well as the utility of economic coercion as a strategic weapon in the U.S. foreign-policy arsenal, is still very much an open question.

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.