DETERRENCE IS A simple concept: using the threat of force to stop an enemy from doing something. On paper, America should have no trouble restraining Iran thus. The former has a globe-striding army; the latter still relies on warships and fighter jets that predate the Moon landing. In practice, though, Iran has proved devilishly difficult to deter. It is hard to put off insurgents and militias through air campaigns; their goals are attrition and survival, not well-ordered governance, and they are willing to sustain casualties. Full-scale invasion is the only real way to deter them and the history of such interventions is salutary.
Since October the Islamic Republic’s proxy militias in Syria and Iraq have carried out more than 160 attacks on American troops. Some were harmless—more theatre than threat—but not the one on January 28th, which killed three American soldiers at a base in north-eastern Jordan. The Houthis, meanwhile, an Iranian-backed militia in Yemen, have for months waged a campaign of missile and drone attacks against commercial ships in the Red Sea, choking off a waterway that handles perhaps 30% of global container trade.
America has begun to hit back. On February 3rd it bombed more than 85 targets in western Iraq and eastern Syria, the first round of what Joe Biden, the American president, promised would be a multi-stage response to the drone attack in Jordan. It struck the Houthis the next day and again on February 5th, part of a campaign against the group that has so far lasted a month. Yet the attacks from Iranian-backed militias continue, even after the strikes ostensibly meant to deter them.
Mr Biden’s hawkish critics think they know why: American threats are not credible because America is unwilling to strike Iran itself. “The Biden administration can take out all the Iranian proxies they like, but it will not deter Iranian aggression,” said Lindsey Graham, a Republican senator from South Carolina. Instead they call for direct attacks on Iranian territory; they point to the example of Operation Praying Mantis, during the “tanker wars” of the 1980s, in which America sank five of Iran’s warships and destroyed two of its oil platforms in the Persian Gulf.
Critics on the left make a different argument. They see talk of deterrence as misguided warmongering and instead offer what they say is a simple solution: end the war in Gaza. If Israel stops killing Palestinians, Iranian-backed militias might stop their own violent acts.
Both arguments miss the mark. It is true that hitting Iran’s navy in 1988 compelled it to reduce its attacks on oil tankers (and stop targeting Americans altogether). But the Iran of 1988 was exhausted from a ruinous eight-year war against Saddam Hussein’s Iraq and bereft of strong allies. It had no choice but to back down. The Iran of today, by contrast, has a powerful network of proxies and some degree of support from both Russia and China. A round of American strikes might make it even more inclined to use those proxies—and, perhaps, to dash for a nuclear bomb as insurance against future attacks.
As for the Gaza war, many of Iran’s proxies do cite the conflict as justification for their acts. But history did not start on October 7th. Militias in Syria and Iraq have carried out dozens of attacks against American troops over the past decade. The Houthis, too, have a record of attacks on shipping. In 2018 they fired a missile at a Turkish cargo ship carrying wheat to Yemen; in 2019 they briefly seized two South Korean vessels. The war is merely an excuse to escalate what they were already doing.
America’s struggle to deter Iran stems from deeper contradictions in its Middle East policy, namely its desire to pivot away from the region while simultaneously keeping troops in it, leaving a military presence big enough to present a menu of targets but too small actually to constrain Iran.
This reverse-Goldilocks arrangement had deadly consequences on January 28th. The drone attack in Jordan hit an outpost known as Tower 22, a logistics hub for nearby al-Tanf, a remote American garrison in Syria close to the tripartite border with Iraq and Jordan. Established during the campaign against Islamic State, no one can quite explain why al-Tanf still exists (one diplomat calls it a “vestigial limb”). American officials cite a range of missions, from protecting a nearby refugee camp to monitoring Iranian supply lines into Syria. In practice, though, it mostly serves as a bull’s eye for Iranian-backed groups whenever they want to lash out at America.
The Iranian regime views its proxies as vital for its survival: they are fighting a long war of attrition to drive American troops from the Middle East and hobble America’s allies in Israel and the Gulf. Deterrence can only work if that perception changes. Air strikes telegraphed a week in advance will not do the trick, nor will parading aircraft-carriers and long-range bombers through the region, as America has done repeatedly in recent years.
Perhaps Iran could be dissuaded from using its proxies if it believed America was prepared to topple the regime of the Islamic Republic. After two decades of failed American adventures in the Middle East, though, neither Americans nor Iranians believe that. Even Donald Trump, who embodied Richard Nixon’s “madman theory” of foreign policy, stopped short of attacking Iran directly.
American allies in the region do not believe it either. A decade ago, Israel and some Gulf states might have cheered American strikes on Iranian proxies. Then as now, the region was ablaze: Iran was helping Bashar al-Assad turn Syria into a charnel house, and the Houthis were sweeping down from their northern redoubts to seize control of most of Yemen’s population centres. A sustained campaign of American strikes might have changed the course of civil wars in both countries.
Today, though, those wars are basically settled—in favour of Iran’s allies. The regime has its hooks deep in four Arab countries, and a few scattered sorties will not dislodge them. That is why Saudi Arabia and the United Arab Emirates have both tried to improve their relations with Iran: if America cannot protect its partners, they reckon détente through diplomatic engagement and economic incentives is a safer alternative.
In a briefing with reporters after the strikes in Syria and Iraq, American officials made no mention of deterrence. Instead they talked of trying to “degrade” the capabilities of Iranian-backed groups. That might be a more realistic goal: if America blows up enough Houthi anti-ship missiles, they will have to stop firing (at least until Iran can deliver more).
But that would require a prolonged campaign of the sort that Mr Biden may wish to avoid, which gets back to the crux of the problem. In the Middle East America is torn between leaving and staying and cannot decide what to do with the forces it still has in the region. The status quo is not working—and, paradoxically, it is Iran that has deterred America from changing it. ■