President Biden can’t avoid responding to the killing of three American soldiers in Jordan. But his response shouldn’t include a strike on Iran.
The attack Sunday by Iranian-backed militias against a U.S. facility in northeastern Jordan, which killed three U.S. troops and injured more than 30 more, has understandably caused shock and outrage in Washington. U.S. retaliation is assured, although we don’t know what form that retaliation will take. President Joe Biden said Tuesday that he has made a decision about how to respond, and it wouldn’t be a stretch to assume any U.S. military action will be broader in scope than the U.S. strikes against Iraqi and Syrian militia sites over the last three months.
Some pundits and lawmakers want Biden to include Iran itself on its list of targets. “The only thing the Iranian regime understands is force,” Sen. Lindsey Graham, R-S.C., wrote in a statement after the attack in Jordan. “Until they pay a price with their infrastructure and their personnel, the attacks on U.S. troops will continue.” Sen. Tom Cotton, R-Ark., said anything less than an attack on Iran itself would amount to cowardice on our part and embolden Iran’s leaders.
Underlying all of this chest-thumping is the assumption that U.S. military action would be so painful that Iranian leaders would respond the way we would like them to: by standing down and ordering their proxies in the Middle East to cease further attacks against U.S. troops and installations in the region. Unfortunately, this is a low-probability scenario. Iran’s reaction might confound our expectations. Embarrassed and angered after being struck by American bombs, Iran could up the ante and attack U.S. troops and bases. Washington’s extensive military presence in the region, while commonly viewed as a source of strength, may prove to be a vulnerability by providing Iran a long menu of targets to strike.
U.S. officials are quick to say the U.S. will act “at a time and place of its choosing.” But the U.S. doesn’t have a monopoly on choosing when and where to attack. If Iran were attacked, then it, too, would most likely take time to explore its options before responding, and that response might not be immediate. It also might not be what American leaders anticipate. The roughly 45,000 U.S. troops stationed in the Middle East would have to be placed on high alert for an extended period, if only to prepare for the worst. U.S. forces in Iraq and Syria, who have already been attacked more than 160 times since mid-October, would be at the most risk.
Iran’s retaliation could range from using ballistic missiles to strike U.S. bases in Iraq and Syria to stepping up its shipments of weapons to militias aligned with it. The commander of U.S. forces in the Middle East estimates that Iran possesses thousands of ballistic and cruise missiles, more than any other state in the region. At least some of those missiles can reach large U.S. bases, including Al Udeid Air Base in Qatar, the U.S. Navy’s Fifth Fleet based in Bahrain and Al Dhafra Air Base in the United Arab Emirates, as well as Jordan’s Muwaffaq Salti Air Base.
Iran could also retaliate more discreetly and decide not to go against the U.S. in a conventional conflict it would surely lose. While Iran’s conventional military power is lacking — its air force relies on parts from the 1970s, its land forces haven’t fought a war since the 1980s, its navy can’t project beyond a limited area and is primarily focused on defending Iranian territorial waters from foreign attack — Tehran’s proxy network is formidable and well-suited to using asymmetric tactics against a superior adversary.
Lebanese Hezbollah, for instance, possesses about 150,000 missiles, some precision-guided, that could reach all of Israel’s major cities; destroy civilian infrastructure, like airports, ports and the electricity grid; and essentially shut down the country during a full-scale conflict.
The Houthis, the militia-turned-de facto government in Yemen, have already demonstrated their resolve to fight by conducting dozens of attacks against commercial ships in the Red Sea, disrupting global supply chains and forcing large corporations like BP to stay clear. Even U.S. warships aren’t immune from Houthi anti-ship missiles.
Let’s set these details aside and return to the larger point. Those pressing for U.S. military action against Iran wrongly assume that Tehran would necessarily buckle under American pressure. Tehran’s behavior during the last five years invalidates this belief.
When the Trump administration withdrew from the Joint Comprehensive Plan of Action in 2018 and put maximum pressure on the Iranian economy, Iranian leaders retaliated by increasing the quality and quantity of their uranium enrichment and targeting oil tankers in the Persian Gulf. After Trump ordered the assassination of Iranian Gen. Qassem Soleimani in January 2020, Iran targeted a U.S. base in Iraq using ballistic missiles. (Miraculously, no Americans were killed.) And when Israel ratcheted up its attacks on Iranian vessels at sea, Iran mimicked Israeli tactics by going after Israeli-owned ships. 
President Biden can’t, of course, avoid a response to the killing of three American soldiers. But those advising him to go after Iran directly shouldn’t assume they know how Iran will react. Nor should they assume that the consequences of an Iranian response can be predicted or managed.