The Diplomatic and Policy Timeline Leading Up to Operation Epic Fury

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On February 26, 2026, Oman’s foreign minister said U.S.-Iran nuclear talks had made significant progress. U.S. and Israeli forces began striking Iran on February 28. Technical talks had been planned for Vienna the next week.

President Donald Trump said Iran had rejected repeated attempts to make a deal and tried to rebuild its nuclear program. He authorized Operation Epic Fury. Trump said the campaign would destroy Iran’s missile industry and navy and prevent an Iranian nuclear weapon. The decision to strike followed an unresolved dispute over uranium enrichment and a White House judgment that waiting had become too dangerous, even as Oman still planned more talks.

What made more talks unacceptable to the White House? The answer begins with the terms each side brought to the negotiations, and with what nuclear inspectors could not verify.

The demands that divided the negotiations

According to the Arms Control Association, U.S. negotiators demanded that Iran end uranium enrichment, dismantle enrichment facilities, and remove its enriched uranium gas.

Before the last Geneva round, Iranian Foreign Minister Abbas Araghchi said an agreement was within reach if diplomacy took priority; he denied that Iran would build a nuclear weapon and defended its right to peaceful nuclear technology. Those positions were not merely different ways to describe the same deal: one side wanted to end enrichment on Iranian soil, while the other sought to preserve a future path to it.

The nuclear talks also addressed only part of the administration’s stated problem with Iran. Trump’s announced objectives included Iran’s missiles, navy and regional proxy forces as well as its nuclear program. Even a verifiable nuclear accord would not, by itself, have settled those separate military concerns unless the sides negotiated them too. That distinction helps explain why the White House could describe a nuclear bargain as insufficient, while critics could still argue that a limited bargain would lower one urgent risk.

The Arms Control Association reported that Iran’s proposed terms still allowed an enrichment program in the future, while the United States insisted on none. That disagreement matters because enrichment can produce fuel for civilian reactors, but the ability to enrich also raises the question of how quickly a country could produce material for a weapon. A negotiator could see the gap as a reason to keep working on limits and inspections, or as evidence that the central security question remained unanswered.

Before the strikes, Arms Control Association analyst Kelsey Davenport argued that renewed talks might lower the risk of nuclear proliferation and create conditions for negotiating a longer-term agreement, while acknowledging that success was uncertain. She proposed a temporary freeze on enrichment and renewed access for International Atomic Energy Agency inspectors while the sides negotiated. That was an alternative to accepting Iran’s position without limits: it would have tested whether verifiable restraints were possible before a comprehensive settlement.

What nuclear inspectors could verify

The International Atomic Energy Agency (IAEA) estimated that Iran held 440.9 kilograms of uranium enriched up to 60 percent as of June 13, 2025. That was a serious proliferation concern, but a dated stockpile estimate is not a measurement of what was in storage on the day of the 2026 strikes. Military attacks in June 2025 had affected Iranian nuclear facilities, according to the IAEA’s February 27, 2026 report.

Iran had not provided the agency with required reports or access to those facilities, so it could not verify their status. The agency also said it could not verify the size of Iran’s uranium stockpile at the affected facilities.

An inspection gap cuts two ways: it leaves more uncertainty about dangerous material, and it limits confident public claims about precisely what Iran had or was doing at that moment. In March 2025, U.S. intelligence assessed that Iran was not building a nuclear weapon, while warning that its enriched-uranium stockpile was unprecedented for a state without one. An intelligence assessment about weapon construction and an inspector’s inability to account for material address different questions; neither erases the other.

The assessment was a snapshot, not a promise that Iran would never decide to build a weapon. The inspector’s February 2026 uncertainty likewise was not proof that Iran had already made that decision. These distinctions matter because an argument for urgency can rest on dangerous capability and poor visibility without resting on a verified finding that a bomb was under construction.

Davenport warned that an IAEA presence could help account for Iran’s 60-percent-enriched uranium and deter its diversion. Her warning did not require treating a bomb as already under construction. It rested on the danger that decision-makers might lose the ability to see a change before it mattered.

The last week of diplomacy

In a February 24 address, Trump warned that he would not allow Iran to acquire a nuclear weapon and alleged that it was rebuilding its program. On February 25, the Treasury Department sanctioned more than 30 people, entities and vessels linked to Iranian petroleum sales and ballistic-missile and advanced conventional weapons production under its maximum-pressure campaign. Pressure and negotiation were moving at the same time; the sanctions were not the end of the talks.

Also on February 25, Iranian Foreign Ministry spokesman Esmaeil Baqaei called U.S. assertions about Iran’s nuclear and missile programs lies. Ahead of the February 26, 2026 Geneva round, Oman’s foreign minister met Araghchi to review proposals Iran would present in the negotiations. The rhetoric had hardened, but the mediator still had proposals to convey.

The Feb. 26 Geneva meeting was the third round of Oman-mediated nuclear talks, the Arms Control Association reported. Oman’s foreign minister then met the U.S. delegation separately to discuss Iran’s proposals and the American response and questions. Its account said the U.S. side raised questions about the proposals, but did not describe a final rejection.

After that round, Oman said the sides had made significant progress and planned technical talks in Vienna the following week. The United Nations secretary-general welcomed continued talks, urged a durable agreement, and said full IAEA verification was essential. These statements do not show that a deal was imminent; they do show that the mediators and the United Nations still saw a negotiating process in motion.

Who chose force, and what Congress knew

A March 1 White House statement confirmed that Trump authorized the campaign. In his written report to Congress, Trump said repeated diplomatic efforts had failed and threats to the United States and its partners had become untenable. The administration’s stated case was not that talks had never happened; it was that continuing them would leave an unacceptable threat in place.

Trump’s March 2 letter reported the February 28 strikes to House Speaker Mike Johnson. He cited his constitutional authority as commander in chief and chief executive in conducting foreign relations. Federal law separately requires a president to submit a written report within 48 hours of introducing U.S. forces into hostilities when Congress has not declared war.

Reporting a use of force is not the same as Congress voting to authorize it. On February 28, Senate Majority Leader John Thune thanked Secretary of State Marco Rubio for updates throughout the week and said he expected administration officials to brief all senators. On March 4, Sen. Adam Schiff and colleagues argued that continued hostilities required express congressional authorization that the administration had not sought.

The legal and political dispute is therefore about more than notice: it is about how long a president may sustain hostilities without an affirmative vote from Congress. Congress later voted on measures directing the removal of U.S. forces from hostilities with Iran, according to a September 2026 Congressional Research Service report.

The House approved three such concurrent resolutions on June 3, July 23 and September 15; the Senate agreed to one of them on June 23 and approved a separate joint resolution on May 19. These were votes about forces already in hostilities, not a prior vote authorizing the February 28 operation.

The strongest competing readings

On March 2, Trump called the operation a response to grave threats and said Iran had ignored warnings not to rebuild its nuclear program. The White House later restated its goals as dismantling Iran’s missile production and naval capability, severing support for regional proxy forces, and preventing a nuclear weapon. In the administration’s reading, the enrichment dispute, the inability to verify nuclear material and Iran’s broader military capabilities made waiting a security risk, even with further talks planned for 2026.

That argument deserves to be measured against the inspection gap rather than dismissed because Oman reported progress. Progress in a negotiation can coexist with a threat that officials consider urgent. The open factual question is what the administration knew about that urgency beyond the evidence it made public.

Oman reported significant progress on February 26 and expected another technical meeting. After the strikes began, Oman warned that the conflict could widen across the region and called for it to stop. A diplomacy-first critic can point to those statements, the absence of a documented final rejection in Oman’s account, and the proposed freeze and inspections as reasons to question the timing of force.

That case does not prove an eventual agreement was available. It asks whether a narrower interim constraint and renewed inspection access were worth testing before military action, given the risk of a wider war. The competing judgments turn on how much risk officials were willing to accept while an unverified nuclear stockpile and an unresolved enrichment demand remained on the table.

The aftermath did not settle the central dispute

In its June 4, 2026 report, the IAEA still could not verify the status of affected facilities and nuclear material after the strikes. Destroying or damaging a facility is not the same as accounting for all material or restoring inspectors’ access. A September 2026 Congressional Research Service report said a June U.S.-Iran memorandum collapsed and fighting continued, including conflict over the Strait of Hormuz.

In its September 1, 2026 safeguards report, the IAEA said Iran had not confirmed the status of affected facilities and associated nuclear material. On September 26, Oman’s foreign minister met a U.S. assistant secretary to discuss keeping communication channels open for continued diplomacy. The channels survived, but the published record does not establish a new settlement or a verified end to the nuclear concern.

Oman’s announcement before the strikes and its work to keep contact alive months later frame the limit of the story. The timeline establishes that officials chose force while a diplomatic process was still active; it does not establish whether that process would have resolved the dispute, or whether force will.

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