The U.S. airstrike that killed Qassem Soleimani, head of Iran's Revolutionary Guard Quds Force, and Abu Mahdi al-Muhandis, a leader of Iranian-backed militias in Iraq, was not simply a sharp departure in the Trump administration's policy toward Tehran. It also marks a larger shift in America's response to Iranian influence and provocations in the Middle East.
President Donald Trump has gambled that an extraordinary escalation will reassert control of an intensifying U.S.-Iran confrontation. It may actually work. But weathering the diplomatic and military fallout will require far greater skill than Trump's team has displayed so far.
The political scientist Robert Jervis once distinguished between the "spiral model" and the "deterrence model" of conflict. In the spiral model, hitting an opponent simply causes him to hit you back; escalation begets escalation. In the deterrence model, hitting an opponent hard enough leads him to back down; a sufficient show of strength can beget de-escalation.
For much of the past two decades, the U.S. has mostly followed the logic of the spiral model in dealing with Iran. Iranian forces and Iraqi proxies under Soleimani's command used improvised explosive devices to kill hundreds of American troops following the U.S. invasion of Iraq in 2003. Yet the George W. Bush administration — while periodically confronting Iraqi Shiite radicals under Iranian influence — mostly refrained from targeting top Iranian operatives such as Soleimani, for fear of provoking escalation with Tehran and a political backlash within Iraq.
The Barack Obama administration also found the logic of the spiral model compelling. Obama never doubted that the U.S. had greater power than rivals. But he worried that Iran and other competitors had a greater intensity of interests within their home regions, and believed that confrontational policies might simply induce confrontational responses.
In dealing with Iran, then, that administration brought great economic, diplomatic and other pressures to bear in hopes of securing a nuclear accord. Yet Obama showed restraint when it came to military or paramilitary confrontations with Iran and its proxies, whether in Iraq, Syria or elsewhere. (The administration did respond militarily, late in Obama's presidency, to attacks by Iranian-backed Houthi rebels on shipping at the entrance to the Red Sea, but in a deliberately restrained way.)
Trump's approach was initially harder to categorize. In some ways, he pursued a policy of maximum antagonism, by pulling out of the nuclear deal Tehran negotiated with the West in 2015 and imposing harsh economic sanctions. But after attacks on oil tankers, Saudi oil facilities and a U.S. drone, all of which the U.S. blamed on Iran, Trump repeatedly held back from any overt military response.
This latest escalation represents an implicit admission that Trump's earlier strategy failed — that economic antagonism plus military restraint had provoked Iran but not adequately deterred it. That failure was confirmed most recently by militia attacks on U.S. facilities and personnel in Iraq, and by the menacing New Year's Eve siege of the U.S. embassy in Baghdad. Meanwhile, Trump's disordered policy had sown doubt among U.S. partners in the Persian Gulf and throughout the region, who worried that Washington might not defend them from Iranian attacks that American policy was helping to incite.