Strikes won't stop Iranian-backed militants. Here’s what they will do. 

To be sure, more Houthi attacks are coming, but the objective, again, is not to stop them from attacking — which is impossible — but to lower the risk these inevitable future attacks pose.

In early January, the United States began launching a series of military strikes on Houthi targets. In early February, the Biden administration expanded strikes to include targets against Iran’s Islamic Revolution Guard Corps and its affiliated militias in Iraq and Syria. 

Many have misinterpreted these strikes, and even argued against them, as unlikely to achieve deterrence. But they are not designed to achieve that outcome.   

Strikes against state-backed militias like the Houthis degrade these groups’ military capabilities. Strikes are the only near-term path to reducing the immediate threat that they pose. They reduce the threat, but they will not deter the Houthis from attacking commercial shipping in the Red Sea — the Houthis’ current target of choice. 

In January, when President Biden was asked by a reporter if he thought the initial strikes were working, his response put it plainly: “Are they stopping the Houthis? No. Are they going to continue? Yes.”  

The same logic applied to the president’s more recent choice of how to respond to the drone and missile attacks by Iraqi and Syrian militant groups, which claimed the lives of three American servicemembers in a border post inside Jordan and along the Syrian border. Once again, President Biden chose to strike while also understanding that such strikes would almost certainly not deter the group from launching additional attacks.  

Such strikes could, however, take key capabilities and leaders off the battlefield, challenging Iran and the militias it backs to field the same quantity and quality of attacks in the future. But that effect will not occur after a few rounds of strikes and there will be times when these militants launch successful attacks despite the military pressure.

Indeed, the same Iraqi and Syrian groups the United States struck showed their resolve by hitting U.S.-supported fighters in Syria with a deadly drone attack days later. And the Houthis continue to attack commercial shipping including severely damaging a cargo vessel, which could ultimately sink. 

Recently, when John Kirby, the White House spokesman on national security matters, was asked about deterring the Houthis, he noted the mission was to “disrupt and degrade.” He has used the same terms to describe the expansion of U.S. strikes in Iraq and Syria. 

Although this may seem like Beltway semantics, the distinction is important: In the immediate term, the objective is not to persuade Iranian-backed militants to change their calculus — that is more or less impossible. It is to limit their ability to conduct effective attacks.  

In the current context, deterrence is nigh unachievable. Despite disingenuous claims to the contrary, none of these groups is going to stop launching attacks. One of the targets of U.S. military action, the Houthis, is already coming off an eight-year campaign of missile and drone attacks that compelled Saudi Arabia to end its own aerial bombing of Yemen. Kataib Hezbollah, another targeted militia group, was part of a prior campaign of 78 attacks against U.S. forces in the 2021-2023 period.  

The United States is rightfully expanding its operations against these groups to degrade their military capabilities, and a sustained campaign holds promise for lessening the threat they pose to U.S. interests. Those interests are not abstract — they encompass the protection of U.S. personnel as well as the freedom of navigation through the Red Sea, a key choke point in global trade. 

The United States and its allies supporting the military mission — including the United Kingdom and Canada in the case of the action against the Houthis — possess the means to threaten these groups’ leadership, as well as their ability to perform reconnaissance and launch missiles and drones. Until recently, the United States has relied overwhelmingly on defensive action — shooting launched missiles and drones out of the sky — rather than going directly after these groups. 

The start of the campaign against the Houthis, however, has followed a promising blueprint: Carrier-launched aircraft have used both deliberate, preplanned strikes to hit Houthi radar, air defenses, launchers, missiles and drones. On-call strikes have been used to hit targets such as equipment the Houthis unearth from hide sites to prepare for an impending attack.  

These types of strikes are challenging because much of the Houthi’s kit is mobile. But early U.S. assessments are that a couple dozen rounds of strikes have already degraded the Houthis military capabilities. 

To be sure, more Houthi attacks are coming, but the objective, again, is not to stop them from attacking — which is impossible — but to lower the risk these inevitable future attacks pose. A key is to deprive the Houthis of the ability to field complex attacks that marry drones, cruise and ballistic missiles. The same type of campaign will be necessary against Iran-backed Kataib Hezbollah in Iraq and Syria.    

When these state-backed militia groups launch subsequent attacks, which they will, critics of the policy are likely to repeat the mantra that these military actions do not have the intended deterrent impact. A fairer assessment would be whether the U.S. military strikes are degrading the groups’ ability to launch the scope of attacks the groups would have absent the intervention.

Either way, the attacks are coming. Supporting a U.S. policy that holds the potential to make them less effective is the only way to diminish their impact in the near term.  

Jeff Martini is a senior researcher at the Rand Corporation. Gian Gentile is the deputy director of the Rand Corporation’s Army Research Division.