Iran vs. USA: How Did the 2026 Conflict Begin and What Happens Next?

Explainer By Y-Trendz

What began as one more round of failed nuclear diplomacy exploded, on February 28, 2026, into the most significant war the Middle East has seen in decades — one that killed a sitting head of state, dragged in half a dozen countries, closed the world's most important oil chokepoint, and is still not fully resolved four months later. Here's how it happened, and where things stand.

The Roots: Four Decades of Distrust

The hostility between Washington and Tehran predates almost everyone currently negotiating between them. It traces back to the 1979 Islamic Revolution and the year-long U.S. embassy hostage crisis that followed, which set a tone of mutual hostility that has shaped the relationship ever since. Iran's ballistic missile program grew out of the 1980s Iran-Iraq War, when Tehran needed a way to strike back at Iraqi cities without a modern air force, itself a legacy of Western sanctions.

The nuclear dimension entered the picture in 2002, when Iran's covert enrichment activities were first exposed. A 2015 deal, the Joint Comprehensive Plan of Action (JCPOA), froze the program in exchange for sanctions relief — but in 2018, the first Trump administration withdrew from it, arguing it never addressed Iran's missile program or its support for militant groups across the region. The resulting U.S. sanctions triggered Iran's worst economic crisis in forty years, cutting its oil exports by more than half and emboldening hardliners in Tehran. Iran responded by abandoning the deal's enrichment caps and curtailing international inspections.

A first direct war actually predates the 2026 conflict: the "Twelve-Day War" of June 2025, in which Israel launched a surprise attack on Iranian military and nuclear facilities, assassinating military leaders and nuclear scientists, prompting Iranian retaliation with over 550 ballistic missiles and 1,000 drones before the U.S. bombed three Iranian nuclear sites and a ceasefire was reached. That episode left Iran weakened but unbowed — and set the stage for what followed.

The Immediate Buildup

Tensions resumed climbing in January 2026, as Iran's government violently suppressed a fresh wave of anti-government protests fueled by economic collapse and infrastructure failures. The regime was arguably at its weakest point in years: extensive protests illustrated its weakened legitimacy, while many of Iran's regional allies had already been significantly degraded by earlier Israeli military action.

Diplomacy briefly seemed to be working. The U.S. and Iran opened indirect talks in Oman in February, and by late in the month Iran had reportedly made a surprising offer on its nuclear program. Omani mediators said a "breakthrough" had been reached just a day before the war began, with Iran agreeing to never stockpile enriched uranium, submit to full IAEA verification, and irreversibly downgrade its enriched uranium stockpile. But the U.S. simultaneously undertook its largest military buildup in the region since the 2003 Iraq invasion, deploying two carrier strike groups and hundreds of aircraft, while accusing Iran of secretly advancing weapons capable of threatening American interests.

February 28: The War Begins

On February 28, 2026, following what U.S. envoy Steve Witkoff characterized as a collapsed third round of talks, the United States and Israel launched coordinated strikes — Israel's codenamed Operation Roaring Lion, America's Operation Epic Fury. The Israeli Air Force began an unprecedented wave of decapitation strikes; Supreme Leader Ali Khamenei and several high officials attending meetings at his residential compound were killed, along with members of his family, while U.S. warships fired Tomahawk missiles and stealth bombers struck fortified missile facilities.

The scale was staggering: U.S. and Israeli forces launched nearly 900 strikes in just 12 hours, targeting missiles, air defenses, military infrastructure and leadership — killing Khamenei and dozens of officials, but also roughly 170 people when a missile struck a girls' school in the town of Minab. That strike on the Shajareh Tayyebeh school became a defining symbol of the war's civilian toll and drew international condemnation even from governments sympathetic to the strikes' broader aims.

Iran did not stay down long. Within hours it launched missile and drone attacks against Israel and U.S. bases across the region, and within days, Hezbollah opened a northern front from Lebanon, with Israel retaliating against Beirut and southern Lebanon — transforming a bilateral operation into a broader regional war involving multiple armed actors. Gulf states hosting U.S. forces, including Qatar and Bahrain, came under fire; Qatar arrested an alleged Iranian intelligence cell operating on its soil, and energy companies across the Gulf began declaring force majeure on oil and gas exports as the fighting spread.

A War at Sea, and a Leadership Vacuum

The naval dimension of the conflict proved unusually dramatic. U.S. forces reported destroying 19 Iranian ships and a submarine, along with nearly 2,000 targets overall, while a U.S. submarine sank an Iranian frigate off Sri Lanka's coast, killing dozens of crew. Iran, in turn, seized control of the Strait of Hormuz — the corridor through which roughly a fifth of the world's oil transits — and began charging tolls on shipping, sending crude prices climbing and threatening a global energy shock.

Domestically, Khamenei's death left Iran scrambling to avoid a power vacuum. Israeli strikes destroyed the building where Iran's Assembly of Experts was expected to convene to select a new supreme leader, delaying the succession process. In the interim, Ali Larijani, a widely trusted senior official serving as secretary of the Supreme National Security Council, was believed to be Iran's de facto leader, before Mojtaba Khamenei — considered more hawkish and repressive than his father — was appointed the new supreme leader in early March, despite reported U.S. objections. President Trump, for his part, initially called for regime change outright, though he later said it had already occurred while making clear he distrusted Iran's new leadership.

By the time a first ceasefire took hold, HRANA (Human Rights Activists News Agency) estimated Iranian strikes had left at least hundreds dead and thousands wounded inside Iran alone, with additional casualties across Israel, Lebanon and Gulf states, and millions displaced regionally.

The Fragile Path to Ceasefire

Fighting continued through March and into April, including a limited Israeli ground incursion into southern Lebanon. On April 8, Pakistan announced that Washington and Tehran had agreed to a two-week pause — but the truce proved shaky almost immediately. Hours after the ceasefire announcement, the IDF conducted strikes across Lebanon that killed hundreds and wounded more than 1,000, straining the agreement amid disputes over whether Lebanon was even covered by it. Trump later confirmed Lebanon was excluded specifically "because of Hezbollah."

Negotiations dragged on through the spring with repeated setbacks — Trump canceled one round of Islamabad talks in April, citing divisions in Iranian leadership, and reportedly set five tough preconditions in May, including that Iran hand over 400 kilograms of enriched uranium and accept only one operational nuclear facility. But by late May, momentum built again, and on June 17, Trump and Iranian President Masoud Pezeshkian remotely signed what became known as the Islamabad Memorandum — a 14-point memorandum of understanding setting a 60-day ceasefire period during which further talks would address unresolved issues, including uranium enrichment levels, reopening the Strait of Hormuz to shipping, ending hostilities in Lebanon, and the possible release of up to $25 billion in frozen Iranian assets.

Even this didn't hold cleanly. Barely eleven days after signing, the ceasefire was already on shaky ground amid renewed strikes by both sides and a Trump threat to restart the war and "complete the job," sparked by competing interpretations of the memorandum's terms on the Strait of Hormuz. A subsequent high-level meeting in Switzerland in late June produced what U.S. Vice President JD Vance called a "foundation" rather than a finished "house" — including Iran's agreement to invite IAEA inspectors back into the country, a milestone Vance called a first step toward permanently ending Iran's nuclear weapons capability, along with coordination mechanisms for the Lebanon ceasefire and demining the Strait.

Where Things Stand Now

As of early July 2026, the situation remains a genuine ceasefire — but a tense and incomplete one. Indirect, technical-level talks between U.S. and Iranian officials have continued through Qatari and Pakistani mediation in Doha, described by Vance as "going well," though one analyst noted the agreement seems hung up in its own clauses, with the sides not yet even discussing the nuclear issue but rather the implementation of Lebanon and Hormuz commitments from the original memorandum.

Iran, meanwhile, has spent the first week of July mourning Khamenei in an enormous state funeral, with processions running from July 4 through July 9 and burial planned at the Imam Reza Shrine in Mashhad — ceremonies expected to draw between 15 and 20 million mourners. Talks were formally paused during this period, with mediators saying the next round would be scheduled "at the earliest possible time" afterward. Adding to the uncertainty, Mojtaba Khamenei, Iran's new supreme leader, has not appeared publicly since the war began, fueling speculation about his health or standing, with his brothers standing in for him even at his own father's funeral.

Genuine sticking points remain substantial. Iranian negotiator Mohammad Bagher Qalibaf has publicly rejected reports of expanded inspection access as "lies," insisting IAEA inspectors remain barred from any bombed or damaged site and limited to just two locations nationwide. Iran continues to insist on retaining the right to enrich uranium in some form, something Washington has flatly rejected, demanding "zero enrichment." Trump has said recovering Iran's existing enriched uranium stockpile is less urgent than reopening Hormuz to shipping, and has floated letting Iran keep ballistic missiles only "in relative proportion" to Gulf neighbors — an idea the Gulf Cooperation Council has pushed back on, insisting any final deal must limit Iran's missile capability. Meanwhile, Hezbollah has refused to disarm absent an Israeli withdrawal from Lebanon, and Netanyahu has vowed Israeli forces will stay until any threat is eliminated — meaning the Lebanon front remains a live flashpoint that could reignite the broader war even if the U.S.-Iran track holds.

What Happens Next

The 60-day clock set by the June memorandum is ticking, with the most substantive nuclear negotiations — the actual core of the dispute — still not properly underway. Technical talks are expected to resume in Doha or a similar venue once Khamenei's funeral rites conclude, likely around July 11, with Islamabad also mentioned as a possible venue for higher-level engagement. Trump has continued to publicly threaten renewed military action — warning Iran to "make a deal or finish the job" — while insisting he doesn't want to further damage a country of 91 million people if a deal can be reached instead.

The likeliest near-term path is neither full peace nor renewed full-scale war, but a continuation of the current pattern: incremental, technical agreements on shipping and frozen assets, punctuated by sharp rhetorical clashes over the unresolved core issues of enrichment and inspections, with the ever-present risk that any single incident — a strike in Lebanon, an incident in the Strait, or a breakdown in Doha — could collapse the fragile truce entirely. With Iran's actual seat of power still opaque following Mojtaba Khamenei's prolonged public absence, much may depend on internal Iranian politics that outside negotiators can't fully see or control.