A large-scale Israel–U.S. attack on Iran began on February 28, 2026, after a prior major Israel–Iran clash in June 2025 that ended in a fragile ceasefire but left the underlying nuclear/missile dispute unresolved. In early 2026, U.S. economic coercion intensified and diplomacy appeared to have stalled; the February 28 operation was publicly justified by the Trump administration as a means of protecting U.S. “core national security interests” and eliminating Iran’s nuclear/missile threat, while Israeli leaders framed it as removing an “existential threat” and explicitly encouraged regime change. Iran responded with wide regional counterstrikes against U.S., Israeli, and host-country targets across the Gulf and broader Middle East, creating a fast-moving, multi-theater conflict with major escalation risks—especially to energy flows, allied basing, and shipping. (UK Parliament briefing, Mar 2, 2026 , Iran Watch, Mar 2, 2026, PBS/AP, Feb 28–Mar 2, 2026)
Why the Israel–Iran Conflict Escalated in 2025–2026
Iran’s nuclear program and “breakout” risk
Multiple sources converge that the operational and political center of gravity was Iran’s nuclear program (enrichment, hardening/undergrounding, and “breakout” anxiety) plus its ballistic missile and drone capabilities—seen by Israel as existential and by the U.S. as a core national security concern. (Bulletin of the Atomic Scientists, Jul 15, 2025: UK Parliament briefing, Mar 2, 2026).
Coercion plus diplomacy: How pressure campaigns shaped the escalation
By 2025, U.S. posture combined negotiations with military signaling, and analysis at the time explicitly framed a “Plan B” logic: diplomacy preferred, military option preserved, and Israeli preventive-strike doctrine looming if talks failed. (Bulletin of the Atomic Scientists, Jul 15, 2025.).
Regional proxies and air/missile defense pressures
Iran’s network of regional partners and proxy capabilities (including missile/drone pressures on Israel and U.S. interests) contributed to an operating environment in which escalation could propagate quickly beyond Israel–Iran. For example, Houthi strikes on Israel (including a ballistic missile aimed at Ben Gurion Airport) persisted even amid partial U.S.–Houthi understandings, underscoring the broader “regional fires” dynamic. (ISW, May 9, 2025).
Timeline of Key Events (Early 2025 to February 28, 2026 attack)
March 2025: U.S. export controls and Iran procurement networks
The U.S. Department of Commerce (BIS) added entities to the Entity List, including Iran-linked procurement actors described as supporting Iran’s defense/UAV programs—an early 2025 marker of intensified coercion tools alongside diplomacy (DOC/BIS Final Rule, Mar 28, 2025, “Additions and Modifications to the Entity List”).
June 2025: Israel–Iran war cycle and U.S. strikes on nuclear facilities
June 12–25, 2025 features a concentrated Israel–Iran war cycle:
- Israel launched an air campaign starting June 12 targeting Iran’s nuclear program and regime-linked capabilities, including strikes on nuclear-related sites and IRGC/missile infrastructure. (ISW, Jun 19, 2025)
- Iran responded with large missile barrages and escalation in missile types and salvos (ISW, Jun 19, 2025).
- Reporting around the end of the June 2025 conflict indicates U.S. strikes hit Iranian nuclear facilities and that a ceasefire was announced for June 25 after a 12-day conflict, though exchanges continued up to the ceasefire window, and assessments suggested the nuclear setback was limited in duration. (Times of Israel liveblog entry, Jun 24, 2025; Times of Israel liveblog entry, Jun 25, 2025)
June 2025 looks like the “failed reset”—a major kinetic episode that did not permanently resolve nuclear/missile concerns and left both sides preparing for renewed confrontation (Times of Israel liveblog entry, Jun 24, 2025; (Bulletin of the Atomic Scientists, Jul 15, 2025)
Late 2025: U.S. strategic framing and nuclear threat posture
U.S. Senate discussion of an “arms race” environment placed Iran among core proliferators/modernizers and treated preemptive actions as having prevented Iran from obtaining nuclear weapons—signaling continued elite-level salience. (Senate hearing, Dec 10, 2025, “Hearings To Examine Arms Race 2.0”)
February 2026: new U.S. economic coercion tools ahead of the strikes
The White House issued Executive Order 14382 (published Feb 11, effective Feb 7) creating new tariff authority targeting foreign countries that purchase Iranian goods/services, reinforcing the broad coercion architecture in the weeks before the February 28 strikes. (EOP Presidential Document, Feb 11, 2026, “Addressing Threats to the United States by the Government of Iran”)
Feb 28–Mar 3, 2026: strike tempo and expanding target sets
On February 28, Israel and the U.S. began a major joint assault, striking leadership/security forces and military infrastructure. The UK Parliament briefing summarizes the operation as targeting leadership, security forces, nuclear facilities, and missile sites, and explicitly notes a regime-change
intent attributed to the campaign (UK Parliament briefing, Mar 2, 2026 , Iran Watch, Mar 2, 2026).
Public justifications and declared objectives:
- The UK Parliament briefing reports President Trump stated Iran threatened “core national security interests of the US,” and the U.S. framed action as self-defense under the UN Charter.
- Iran Watch reports Trump’s stated objectives included destroying Iran’s missile capabilities and preventing regional destabilization or acquisition of nuclear weapons; Netanyahu is reported to have explicitly stated regime change as the goal.
- Al Jazeera reports Netanyahu publicly urged Iranians to mobilize to overthrow the regime following Khamenei’s killing, reinforcing the regime change messaging (Al Jazeera, Mar 3, 2026).
Immediate operational tempo: sustained strikes into early March
- Reuters reported a new wave of Israeli strikes on Tehran on March 2, preceded by evacuation warnings near the state broadcaster IRIB. (Reuters, Mar 2, 2026)
- The UK Parliament briefing describes roughly 2,000 strikes by early March (noting verification constraints due to restricted access) (UK Parliament briefing, Mar 2, 2026).
Iran’s Regional Retaliation: Bases, Partners, and Host-Country Targets
Where Iran struck across the Gulf and the wider Middle East
The UK Parliament briefing states Iran launched counterstrikes against Israel, U.S. military bases, and locations in Arab states hosting U.S. forces; it also notes UK bases in Bahrain, Qatar, and Cyprus were attacked and the RAF deployed defensively.
Iran Watch similarly catalogs Iranian missile/drone attacks spanning Bahrain, Jordan, Kuwait, Oman, Qatar, Saudi Arabia, the UAE, Lebanon, Iraq, Cyprus, and Syria.
Iran’s retaliation pattern appears designed to (a) impose costs on U.S. basing and
coalition sustainment, (b) pressure host governments, and (c) create coercive leverage via energy/shipping risk.
Strait of Hormuz and Energy Shipping Risk: What to Watch
The UK Parliament briefing reports that Iran threatened to close the Strait of Hormuz, while other reporting describes the dynamics of major disruption and oil market anxiety (Brookings, Mar 2, 2026).
Civilian Harm and Information Constraints
- A Times of Israel liveblog entry cites an Iranian governor claiming 40 killed in a strike on a girls’ school in Minab on Feb 28. (Times of Israel, Feb 28, 2026)
- Other reporting (e.g., Al Jazeera) attributes much higher casualties at a girls’ school, illustrating significant uncertainty and potential information disorder around singular incidents. (Al Jazeera, Mar 3, 2026).
- The UK Parliament briefing emphasizes the difficulty of verification due to restricted internet/media access in Iran. (UK Parliament briefing, Mar 2, 2026).
Ultimately, treat specific casualty figures as provisional; the more reliable point is that civilian harm is being reported across multiple theaters and is likely to increase as strikes persist.
International Reactions: Where Allies Align and Where They Split
UN Security Council dynamics and major-power positions
The UK Parliament briefing reports an emergency UN Security Council session without a resolution and notes UN Secretary-General Guterres condemned the violence and urged diplomacy; it also records Russia and China condemning the U.S.-Israeli strikes.
PBS/AP reporting similarly describes Russia and China criticizing the strikes and accusing the U.S./Israel of pursuing regime change under the nuclear pretext. (PBS/AP, Feb 28–Mar 2, 2026).
Europe’s posture: distance from the initial strike, defensive cooperation against retaliation
Iran Watch reports the E3 (France, Germany, UK) “distanced themselves” from the U.S.-Israeli action while condemning Iran’s regional strikes. (Iran Watch, Mar 2, 2026)
PBS/AP adds that the UK/France/Germany called for renewed talks and were also prepared to help prevent further Iranian missile/drone attacks—suggesting a practical shift toward defensive cooperation even if they did not endorse the opening strike. (PBS/AP, Feb 28–Mar 2, 2026).
Gulf and Arab states: sovereignty pressure and basing politics
PBS/AP reports multiple Gulf states urged Iran to halt attacks and emphasized self-defense, while the Arab League condemned Iranian attacks as sovereignty violations; notably, Syria also condemned Iran, reflecting shifting regional alignments.
What Happens Next: Escalation Scenarios and Signposts
Scenario 1: Prolonged air campaign and expanding target sets
Trump and senior U.S. officials signaled continued operations; Reuters reported continued waves on Tehran; and reporting describes sustained operational tempo. (Reuters, Mar 2, 2026).
Risks/implications:
- Higher probability of mass-casualty events and infrastructure collapse dynamics.
- More opportunities for miscalculation involving third-country air defenses and coalition basing.
- Greater chance Iran leans into asymmetric maritime disruption.
Signposts:
- Evacuation warnings in Tehran and strikes on state/broadcast infrastructure indicate widening coercive messaging and psychological operations.
Scenario 2: Negotiated de-escalation and why it’s hard now
International pressure is focused on returning to talks; Oman is repeatedly referenced as a diplomatic channel; and European leaders explicitly urged resumption of nuclear talks. (PBS/AP, Feb 28–Mar 2, 2026).
Regime-change rhetoric reduces bargaining space; Iran’s broad regional strikes deepen host-country grievances; and leadership decapitation (reported) complicates command-and-control and credible commitments. (UK Parliament briefing, Mar 2, 2026 , Iran Watch, Mar 2, 2026).
Signposts:
- Any shift in U.S. public messaging from regime change to narrowly tailored deterrence/self-defense language.
- Restoration of an Oman-mediated track and verifiable constraints around enrichment and missile salvos.
Scenario 3: Regime destabilization and fragmentation risk
Israeli leadership messaging explicitly encourages internal overthrow; strikes reportedly targeted leadership/security apparatus; and multiple analyses warn about instability pathways. (UK Parliament briefing, Mar 2, 2026 , Iran Watch, Mar 2, 2026, Brookings, Mar 2, 2026)
Risks/implications:
- Competing power centers (IRGC factions, clerical networks, regional actors) could produce a security vacuum.
- Proliferation risk increases if nuclear material accounting/verification is degraded. Iran Watch notes IAEA access constraints since June, and the inability to guarantee that diversion did not occur from previously affected sites.
Signposts:
- Reports of security force fragmentation, large-scale defections, or sustained nationwide protests.
- Any IAEA statements about loss of continuity-of-knowledge or material control concerns.
Scenario 4: Maritime and energy war as Iran’s leverage
Iran threatened to close Hormuz and has struck regionally; the strategic payoff of energy leverage is immediate. (UK Parliament briefing, Mar 2, 2026).
Risks/implications:
- Global oil price spikes and shipping insurance shocks.
- Coalition pressure to conduct broader suppression of Iranian coastal/naval assets.
Signposts:
- Mining incidents, tanker attacks, coordinated drone swarms near ports, and sustained missile fire toward refining and export infrastructure.
Scenario 5: U.S. ground involvement: unlikely near-term, watch the indicators
Reuters reports Secretary of State Rubio stating that the U.S. is not currently postured for ground forces and believes objectives can be achieved without them, while keeping the option available. (Reuters, Mar 2, 2026).
Signposts:
- Large U.S. troop movements into theater; medevac/CSAR posture changes; rhetoric about “securing sites” (especially nuclear-related).
Key Uncertainties That Could Change the Outlook Quickly
Leadership outcomes and contested reporting
Some sources describe the killing of Iran’s Supreme Leader; others show uncertainty and contested claims in public discourse. The UK Parliament briefing treats the death as confirmed and describes a transitional council; Iran Watch also reports Khamenei was killed (UK Parliament briefing, Mar 2, 2026).
Battle damage assessment uncertainty
Restricted access means battlefield claims (casualties, facility destruction, institutional breakdown) are especially prone to exaggeration or error (UK Parliament briefing, Mar 2, 2026).
Nuclear end-state ambiguity and verification gaps
Even large strike packages may not permanently eliminate a dispersed, redundant program—an issue already visible in post–June 2025 assessments that suggested limited-duration setbacks. (Bulletin of the Atomic Scientists, Jul 15, 2025; Times of Israel, Feb 28, 2026).
72-Hour Watchlist: What to monitor
- Strike focus: whether Israel/U.S. continue expanding from missile/nuclear/IRGC nodes into state control infrastructure (broadcast, prisons, police, energy) (Reuters, Mar 2, 2026).
- Regional basing resilience: frequency and lethality of Iranian attacks on U.S. bases and host-country sites, and whether host governments constrain U.S. operations (UK Parliament briefing, Mar 2, 2026).
- Hormuz/shipping: credible indicators of closure attempts, mining, or sustained anti-ship operations (UK Parliament briefing, Mar 2, 2026).
- Diplomatic track signals: E3/Oman messaging and any reconstitution of talks framing (PBS/AP, Feb 28–Mar 2, 2026).
- IAEA continuity-of-knowledge: any change in IAEA ability to account for material or access sites (Iran Watch, Mar 2, 2026).