Throughout the U.S.-Israeli war on Iran, Washington has relished the display of its conventional military superiority. President Donald Trump’s administration has boasted of its quantitative achievements: before the April 8 cease-fire, the United States alone flew more than 10,000 air sorties, hit over 130,000 targets, and intercepted 1,700 Iranian missiles and drones. According to U.S. Central Command, the campaign demolished more than 85 percent of the facilities that Tehran used to produce missiles and drones, sank the majority of Iran’s naval vessels, and eliminated 70 percent of its missile launch infrastructure.

But degrading Iran’s military capabilities was not the broad strategic goal Trump laid out in the early days of Operation Epic Fury. He variously promised to achieve the complete surrender of the regime, to protect the Iranian people from their leaders’ brutality, to rid the region of Iran’s malign influence entirely, and to wrest a better nuclear deal from Tehran than the one U.S. President Barack Obama reached in 2015. All these aims remain elusive. The regime in Tehran survived. And it has cleverly adapted toward an attrition strategy that has badly strained the U.S. arsenal, threatened civilian infrastructure across the Middle East, and added a new dimension of power projection by effectively closing the Strait of Hormuz and pressuring the global economy.

Although the U.S. military’s approach to the region has delivered many operational successes, the Iran war has exposed its serious shortcomings and created new challenges. As it demonstrated an unmatched ability to rapidly deploy massive air and sea power, the Pentagon also deepened its relationships with Middle Eastern militaries, especially with the Israeli armed forces, with which it fought its first truly joint campaign since World War II. But Washington’s tactical successes could not make up for its strategic missteps. Its failure to build a fighting coalition beforehand—or even to make the case on the global stage that Iran had become an imminent threat—left it struggling to build international consensus to confront Iran’s asymmetric tactics and finalize a strong postwar deal. And the conflict dangerously ran down the U.S. arsenal. The United States simply cannot afford to fight another war like this one.

Most important of all, the war compromised the United States’ status as the Middle East’s main security guarantor. For decades, U.S. policy toward Iran focused on the three pillars of Iran’s power projection: its nuclear program, its missile arsenal, and its network of proxy militias. Yet degrading each of these pillars was not enough to topple the Islamic Republic or force it to accept a deal that safeguarded either the United States or its partners. Fundamentally, the nature of Iran’s threat has changed in ways Washington was not fully prepared to counter, and Epic Fury only accelerated Tehran’s adaptation. Throughout Epic Fury, Middle Eastern militaries continued to rely on the United States for air defense support and intelligence. But Washington could not fully neutralize Iran before its retaliatory aggression shattered the Gulf’s reputation as a calm, safe, business-friendly haven. Nor could it effectively curb the Islamic Republic once it decided to halt freedom of navigation through the region’s most vital waterway.

In a bitter paradox, the Iran war revealed opportunities for U.S. Central Command to work much more effectively with regional militaries. But the trust deficit that has opened between the United States and its Gulf partners will make it far harder to take advantage of those opportunities. The Gulf states need clearer security commitments now more than ever. These countries, however, are losing faith that Washington is committed to ensuring their security, and both the American public and U.S. political leaders have lost what appetite they had for the costly, sustained work of countering Iran’s threats.

The Middle East after Epic Fury is not safer, more stable, or more prosperous. And if the United States fails to achieve the grand goals Trump set out before the war, its ability to rally partners in other theaters will be undermined, and its adversaries will be emboldened. To properly learn the war’s lessons, the United States has to change how it fights. The U.S. defense industrial base will need to innovate faster and pair with trusted partners in developing and coproducing an arsenal that can meet the demands of future wars. In the Middle East, the Pentagon will need to accelerate changes to its force posture and basing, and update the way it works with allies. Gulf countries are already looking for supplemental defense partners, and Washington must redouble its efforts to transition from being the region’s sole security guarantor to its security integrator. If it fails to do so, it could entrench the idea that the United States will be an impediment, not an asset, to allies as they seek to ensure their security.

The United States had already begun to adjust its military posture in the Middle East years before Epic Fury. After the 1991 Gulf War, the U.S. military rotated forces through bases across eastern Gulf countries—Bahrain, Kuwait, Qatar, and the United Arab Emirates (UAE)—and positioned equipment in preparation for another conventional war. This network of bases subsequently supported the U.S. wars in Afghanistan and Iraq in the first decade of the twenty-first century; in the 2010s, the campaign to defeat the Islamic State, also known as ISIS, and efforts to counter Iranian influence sustained the existing basing structure. But as Washington became more aware of Iran’s growing missile and drone arsenal and the threat it posed to U.S. bases in the Gulf, it began to plan a more agile basing network along the Red Sea and the Mediterranean. By 2020, the Pentagon was developing the Western Access Network, a system of bases intended to circumvent maritime chokepoints and Iran’s short-range threats. It also started to move elements of its aboveground coordination hub from the al-Udeid base in Qatar to South Carolina.

Ahead of Epic Fury, the United States did not mass forces or materiel in Bahrain, Kuwait, Qatar, or the UAE. Indeed, it anticipated that Iran would attack military facilities in those countries with short-range missiles and evacuated troops and military platforms in advance. Instead, Central Command leaders coordinated the war from within U.S.........

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