SIGMA Futures
Middle East · Nuclear-proxy rivalry · 12-month forecast

Iran–U.S.

Probability of conflict between Iran and the United States, on an active-war horizon
27%
below the threshold of combat
73%
kinetic risk over the horizon
2
25
60
13
threshold of combat
Negotiated settlement 2%
No kinetic resolution 25%
Limited military action 60%
Major operation 13%
Two non-kinetic outcomes
Two kinetic outcomes
Settled — a settlement is in place2%
Open — the dispute continues below the threshold of combat, no settlement25%
Both remain below the threshold of combat. They differ in whether the underlying dispute has been settled.
Limited military action — military force is used, short of a major campaign60%
Major operation — a full-scale or multi-axis military campaign13%
Both cross the threshold of combat. The threshold is the use of military force: shots fired, a strike, an armed seizure. Ramming, water cannon and boardings remain below it, however serious, unless military force follows.

A 73% chance of kinetic conflict over the coming year — a war kept going by Iran's power to make escalation expensive and Washington's inability to offer terms Tehran can accept.

The committed forecast
On the record COMMITTED
ledger idIRN-USA · 2026-07
committed2026-07-29
resolves2027-07-29
horizon12 months
frameworkSIGMA
confidencevery wide · ±25 ptsKU
Resolution. Scored at horizon against the realised outcome — no kinetic conflict, a limited action, or a major operation — and logged to the append-only ledger.
Cite this forecast
SIGMA Futures Group assesses a 73% probability of continued kinetic Iran–U.S. conflict over the twelve-month horizon to 29 July 2027, with continued limited military action the modal path at 60%.
SIGMA Forecast Ledger · IRN-USA · 2026-07

This decomposition reflects SIGMA's published judgement as of the assessed date. It is a committed, point-in-time position rather than a live figure; ongoing working analysis is available to members.

Forecast evolution
No kinetic resolution Negotiated settlement Limited military action Major operation
Four-way outcome probability at each committed vintage. Nodes are the assessments; connecting lines are indicative only.
Strategic timeline
Historical
  1. 1953A U.S.- and U.K.-backed coup removes Iranian Prime Minister Mohammad Mossadegh.
  2. 1979The Iranian Revolution deposes the Shah, and students seize the U.S. embassy and hold American personnel hostage.
  3. 1980The United States severs diplomatic relations with Iran.
  4. 1988A U.S. Navy warship shoots down an Iranian civilian airliner over the Persian Gulf.
  5. 1995–96The United States imposes comprehensive trade and investment sanctions on Iran.
  6. 2002The U.S. president names Iran as part of an “axis of evil”.
  7. 2015Iran and the P5+1 conclude the Joint Comprehensive Plan of Action.
  8. 2018The United States withdraws from the Joint Comprehensive Plan of Action and reimposes sanctions.
  9. 2020A U.S. airstrike in Baghdad kills Iranian commander Qasem Soleimani, and Iran launches retaliatory missile strikes on U.S. bases.
  10. 2024–25The United States maintains sanctions while pursuing indirect diplomacy; tensions escalate toward direct confrontation.
Recent developments
  1. June 2025The United States launches Operation Midnight Hammer, striking Iran's nuclear facilities at Fordow, Natanz and Isfahan with B-2 bombers, bunker-penetrating weapons and cruise missiles.
  2. February 2026U.S. and Israeli forces launch a major campaign against Iran, targeting Iranian strategic sites and senior leadership; Supreme Leader Ali Khamenei is killed in the opening strikes.
  3. April 2026A ceasefire takes effect after about forty days of combat.
  4. June 2026The United States and Iran sign a Memorandum of Understanding framing regional-security and nuclear talks.
  5. July 2026The June understanding collapses; U.S. forces resume strikes across Iran after renewed attacks on shipping in the Strait of Hormuz.

Curated for strategic significance, not completeness. The timeline provides context; the Foundation Paper explains the assessment.

Questions this forecast addresses

What are the likely outcomes of the Iran–US war?

Rather than a single prediction, SIGMA's forecast maps the distinct paths the war now under way could take over the coming twelve months, resolving it into four outcomes: its continuation as a bounded war of strikes, blockade, proxy operations, and limited ground action; a de-escalation that falls below active strikes without a formal agreement; a negotiated settlement of the core dispute; and a major escalation, such as a full invasion aimed at occupation or regime change. The committed probabilities for each outcome are set out above.

Will the United States invade Iran?

"Invade" can describe two materially different pathways in this forecast, and SIGMA assigns them to different outcomes rather than to a single figure. A limited seizure of an island, enclave, or stretch of coast is treated as a continuation of the war already under way, within the bounded-conflict outcome. A full invasion aimed at occupation or regime change is a distinct and far more demanding undertaking, tracked separately as the major-escalation outcome. There is therefore no single "probability of invasion" in the assessment; the answer depends on what is meant by invasion.

Will the United States and Iran reach a ceasefire?

SIGMA separates two ways the fighting could subside. A de-escalation winds the conflict down below the level of active strikes without a formal agreement; a negotiated settlement goes further, resolving the core dispute through a durable agreement. The forecast treats these as distinct outcomes because the conditions for the fighting to subside differ from those needed to resolve the underlying dispute. The probability assigned to each is set out above.

What would change this forecast?

The assessment identifies the specific developments that would move it, and ties each to the outcome it would shift. SIGMA tracks these markers, and members receive its interim reading as the situation develops.

Intended use

A calibrated read of one question — to be weighed against your own judgement. SIGMA is designed for decisions where understanding the strategic context matters more than following daily headlines.

Members

Foundation Paper in preparation.

The committed forecast above is the current read on this dyad. Its Foundation Paper is in the programme; the papers published so far are in the member area.

Members

The reasoning behind the forecast.

The Foundation Paper sets out the complete analytical case behind this assessment — the strategic dynamics, the incentives, the competing pathways, and the calibration underlying SIGMA's published forecast. Membership opens the full case, continuing analysis as it develops, and the Strategic Intelligence Dashboard for a wider view of this and other active dyads.

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Related theatres
Other theatres tracked by SIGMA.
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