When will the war end?
Scenario 1: 2-4 weeks
Probability: 20%
President Trump declares victory, citing overwhelming military successes, particularly against Iran’s missile and nuclear programs and regime leaders. We view this as the least likely scenario because Trump cannot credibly declare victory now and because influential Iran hawks at home and Israeli and Gulf leaders are urging him to finish the job in Iran. Also, additional US military capabilities flowing into the region are not likely to arrive and be ready to launch operations in fewer than 10 days.
Scenario 2: 4-6 weeks
Probability: 35–40%
Trump declares victory, as above, and/or the US and Iran agree to end hostilities and reopen the SOH. Reaching such an agreement—whether formal or informal—is likely to take some time and be more achievable after the US and Israel make still more progress against regime targets. In this scenario, Iran’s missile and drone attacks have diminished but not stopped; top-level leaders remain regime stalwarts, even if some of the individual figures change; the security forces remain loyal; and no mass uprisings take place. Also, preparations to open the Strait of Hormuz (SOH) continue.
Scenario 3: >6 weeks
Probability: 40–45%
Trump keeps fighting—and even escalates—because he is angry that he feels backed into a corner and resents rising criticism at home and abroad. He also sees the potential to go down in history as the US president who destroyed the Iranian regime, a goal many in Washington, Israel, and the Gulf are urging him to pursue. Israel and the Gulf states argue that they have already paid the price for the war and now want the US to go all the way to oust the regime.
In this scenario, regime leaders remain cohesive despite more losses, and there is no sign of major unrest. Gulf states are successfully defending themselves against Iran’s dwindling missile and drone attacks but see a post-war future in which Iran uses drones and cyber tools to control the SOH. The US continues to rely on air strikes and naval interdiction against strategic targets (Kharg Island and the SOH) rather than introducing large numbers of conventional forces and begins targeting Iran’s transportation infrastructure and considering military raids to destabilize the regime. This scenario might also involve a US naval blockade of Kharg Island, as Washington tries to strangle Tehran’s oil exports to force it to allow free passage through the SOH.
How will it end?
Scenario 1: A negotiated agreement
Probability: 45–50%
Each side offers the other something verifiable in exchange for peace most likely through a Gulf mediator. The US agrees to stop attacking and stop Israel from attacking, and Iran commits to allowing traffic to flow freely through the SOH. Iran also demands assurances that its assets in Gulf states not be seized as compensation for losses those countries incurred because of Iran’s attacks. Iran may also seek US guarantees that it will not block Iran’s restoring trade relations with, for example, Qatar and the UAE. For its part, Washington insists on getting something in exchange for these assurances, such as a commitment to downblend Tehran’s HEU or turn it over to another country or international organization or consortium. This scenario is most likely because Iran will want some form of formal agreement to end hostilities to avoid the US and Israel mowing the lawn again in several months or years.
Scenario 2: An informal agreement for all sides to stop
Probability: 40–45%
Washington and Tehran exchange messages most likely through a Gulf intermediary. Word is passed that the US will cease attacks and ensure Israel does same so long as Iran reopens the SOH to all international shipping, including the US and Israel. Neither side commits to anything other than stopping the war. In this scenario, Iran concludes it needs a respite from attacks to stabilize the regime, allow its new leaders to meet and discuss strategy, and prevent total economic collapse. In these circumstances, the US might also initially leave naval assets in the region to escort ships through the SOH and raise confidence that they can transit safely.
Scenario 3: Iranian regime collapses, Tehran surrenders
Probability: 10%
In the face of unrelenting US and Israeli bombardment and rising discontent among Iranians, deep fissures develop within the IRGC and other Iranian institutions. Lower ranking IRGC commanders demand change, and members of Artesh (regular armed forces) and Basij (paramilitary) stop reporting to their posts and refuse to take orders, including to fire on protesters. It becomes unclear who is leading Iran, and it takes weeks or even months to identify Iran’s new leaders. They agree to stop attacks and reopen the SOH to all traffic and to open new talks with the US on the nuclear program. This scenario is unlikely given that we are not seeing significant cracks in the system.
How long will the Strait be closed?
Scenario 1: Two to four weeks
Probability: 5%
Trump declares an end to hostilities with Netanyahu’s (grudging) agreement, and Iranian leaders reopen the SOH to try to ensure the US and Israel do not resume attacks. Tehran sees reopening the SOH as a way to begin repairing relations with its Gulf neighbors. The US Navy is likely to retain some vessels in the region, perhaps as part of a multinational coalition, to escort ships through the SOH to raise confidence that normal global shipping can resume safely.
Scenario 2: Four to six weeks
Probability: 45%
Trump aims to wind down the war, but Iran refuses to re-open the SOH without material concessions—such as assurances its assets in Gulf states will not be seized—and security guarantees. The US and Iran engage in indirect talks that result in a cease-fire that paves the way for a negotiated agreement to end the war.
Scenario 3: More than six weeks
Probability: 50%
The US persists and even escalates or the US and Israel stop fighting and Iran keeps the SOH mostly closed until it secures material concessions, as above, and security assurances.
Who will lead Iran in the aftermath?
Scenario 1: IRGC
Probability: 80–85%
The new generation of IRGC leaders dominates the regime, emboldened by the supreme leader to whom it has close ties. This group shares a vision that involves Iran’s being a regional hegemon or, at a minimum, engaging Western and other international actors only on its own terms. Iran continues to be assertive—and at times aggressive—and to embrace a foreign policy characterized by militarism. The IRGC Qods Force, Iran’s external militia and terrorist-building element, will play a key role in defining the post-war environment. A strong Qods Force will be particularly inclined to use missiles, drones, and other asymmetric means to control the SOH and proliferate to partners.
Sub-scenario: Hardline consolidation
Probability: 65%
The IRGC operates largely unchecked and its hardline leaders, like Vahidi, move to consolidate power quickly after the war by brutally suppressing resistance, rebuild Iran’s missile program with help from friends like China and Russia, and decide to test US and Israeli red lines on the country’s missile and nuclear programs.
Sub-scenario: Economic entrenchment
Probability: 35%
The IRGC’s growing clout’s role in the economy makes this a possibility, though one that is likely to play out over months or years rather than weeks.
Scenario 2: Transformational actors
Probability: 10%
The IRGC fractures in response to public pressure or policy divisions, for example, opening the door for a new generation of leaders less weighed down with revolutionary ideology. They demand change that results in peaceful co-existence with the US and Iran’s neighbors and better living standards for the public. They persuade Mojtaba that Iran needs a new approach and embark on reform from within the system. This scenario is unlikely because Supreme Leader Ali Khamenei gradually changed the complexion of the entire Iranian system by appointing more hardliners and ultrahardliners, marginalizing moderates, and excluding reformists. We cannot fully exclude this possibility, though, given how little we know about the regime’s new leaders, how their generation might tackle the country’s problems, and their willingness to act.
Scenario 3: Clerics
Probability: 5–10%
Clerics who studied and taught with Mojtaba in the holy city of Qom eclipse the IRGC in terms of influencing Mojtaba. They cite religious teachings and revolutionary ideology as they exert their influence, which is more likely to moderate foreign than domestic policy. This scenario is very unlikely because the clerics have no control over the levers of power nor influence over the use of force.