The Islamic Republic has managed over the decades to establish Hizballah not only as a powerful military force in Lebanon and a base for terrorist operations but also as a means of exercising political control over the Beirut government and infiltrating the Lebanese military. In Iraq since the early 1980s, and in Syria since 2011, the ayatollahs have been cultivating similar Shiite militias for similar purposes. In an extensive study, Hanin Ghaddar explains how the militias operate, Iran’s plans for them, and what the U.S. can do to counter them:

Through participation, indirect or direct, in various wars and confrontations, . . . Iran has managed to [create] an army of around 200,000 non-Persian Shiite fighters. Individually, these fighters may look scattered and containable, but in reality they are very well organized under the command of the Quds Force, [the expeditionary arm of Iran’s Islamic Revolutionary Guard Corps (IRGC)]. To understand how these militias function, one needs to see them as they see themselves: not as a loose assortment but as a single army with a very clear structure and hierarchy. . . . [M]ost Shiite militias fighting in the region today are organized, trained, and funded by the IRGC and the Quds Force. . . .

While the IRGC still serves as a supervisory entity, Hizballah, Iran’s top Arab Shiite force, is itself training and leading Iraqi, Syrian, Pakistani, Afghan, and Yemeni Shiite militias. Indeed, as Iran’s role in the region grows, so does that of Hizballah. This gives Hizballah more confidence when faced with its other domestic and regional challenges; the group knows that in its next war—possibly with Israel—these Shiite militias will come to its aid. . . .

Meanwhile, Iran has already worked its proxies into Iraq’s military and its political system:

Today, [one Iranian-backed group], the Badr organization, leads the [Iraqi] Ministry of Interior, which allows it to support or undermine provincial police chiefs across the country. The ministry also commands the 37,000-strong Federal Police, a five-division motorized infantry force, and the Emergency Response Division, a divisional-sized special-weapons and tactics group. . . . Since 2005, Badr has likewise controlled the leadership and manning of the Iraqi army’s 5th Division, . . . and is interested in folding [the army’s] dozen or so Popular Mobilization Force brigades into a new Badr-controlled Iraqi army or Federal Police division.

Taken together, these [units] make up the largest concentration of ground forces in the country, outnumbering the functional parts of the federally controlled Iraqi army and counterterrorism service. . . . The key issue for the United States is whether Badr might one day play a role in attacking U.S. personnel or evicting U.S. troops from Iraq. Badr includes many deeply anti-American elements, not least the current minister of interior, Qasim al-Araji, who spent 26 months in U.S. military custody and has been accused of supporting deadly attacks on U.S. personnel. . . .

Tehran [could] use radical Badr members to form another splinter group . . . to deploy in Iraq and in regional struggles such as Syria or Bahrain. Like the Lebanese original, these smaller Iraqi Hizballah clones will be used to attack Iran’s enemies such as Israel, Bahrain, and Saudi Arabia, and possibly to pressure Iraqi political, military, or religious leaders who push back too hard against Tehran’s priorities. Many of these mini-Hizballahs will be partially enmeshed within the security forces, and their part-time involvement in foreign wars with Sunni neighbors will be politically difficult for Iraq’s Shiite prime ministers to prevent. . . .

Yet, Ghaddar concludes, it is not too late for the U.S. to take action to contain Iran.

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.