Q&A: Iran and the US are back on the edge of war. What's coming?

Is a war becoming unavoidable? 

A war is not a foregone conclusion, but the risk is now exceptionally high. Since mid-January, Washington has amassed its largest military buildup in the region since 2003 while pressing for significant concessions in the negotiations that resumed in early February. The scale of the current US military buildup around Iran — which includes multiple carrier strike groups, long-range strike aircraft, air defenses, and extensive logistics and refueling capacity¹ — goes well beyond symbolic signaling. Deployments of this size, estimated at roughly 40-50% of deployable US airpower,² place Washington in a position to initiate rapid military action at the president’s discretion, transforming coercive diplomacy into a credible prospect of war. What remains far less clear is the strategic end Washington ultimately seeks to achieve. 

While Trump’s public vows to support the protesters in Iran formed part of the backdrop to the current escalation, a change in how the Islamic Republic treats its own people has not featured as a core negotiating demand. Instead, this environment of heightened internal instability created openings for the United States to pursue further concessions that the 12-day war failed to secure. Demands for dismantling the nuclear program have remained at the heart of negotiations. But the US has also expanded objectives to include limits on Iran’s ballistic missile program and an end to Iranian support of anti-Israel groups, in line with long-standing Israeli priorities. From Tehran’s perspective, these demands amount to near-total capitulation, making concessions highly unlikely even under severe pressure. A diplomatic path to de-escalation is most plausible if the US pares back its demands to focus on the nuclear program. 

How might a US military confrontation with Iran unfold? 

The US forces currently in place appear more suited to time-bound punitive strikes and regional defense than to a prolonged campaign aimed at regime change or strategic dismantlement. Thus far, the US has no ground forces in place, no meaningful special operations footprint, and no logistical arrangements for a prolonged air campaign.³ This posture suggests that if the US were to use force, it would likely take a phased approach. 

An initial round of targeted strikes would likely seek to impose costs more significant and painful than those of the 12-day war (for more on the 12-day war, see this Q&A). In the previous round, the US conducted strikes on Iran’s three main nuclear facilities, while Israel carried out more than 380 attacks targeting major military and government assets and killing senior commanders and nuclear scientists (see map below). Nevertheless, Tehran retained its stockpile of 60% enriched uranium⁴ and the technical know-how to restart the program, while suspending nuclear negotiations and continuing to reject the principle of zero enrichment. This time, the US could exert additional pressure to test whether Tehran’s calculus can be shifted. If such strikes once again failed to compel concessions, Washington could escalate through repeated strikes or by expanding military assets for a longer campaign.

How far the US would be willing to go remains the central uncertainty. Regime change would require a prolonged campaign, for which there is little political appetite in Washington, and even a leadership decapitation strike would not guarantee that the Islamic Republic would acquiesce to US demands. The trajectory of the crisis, however, remains fluid, and decision-making in Washington under President Trump may depart from conventional escalation logic and cost-benefit calculations, complicating efforts to predict US behavior. 

The role of Israel in any conflict should also not be underestimated. While it has so far taken a back seat as the United States has taken the lead during the recent escalation, its current restraint does not rule out a more active role, given its intelligence reach inside Iran and its long-standing strategic interest in weakening the regime.

How might Tehran react under escalating pressure? Could we see a wider regional conflict?

Iran’s leadership is facing a narrowing set of bad options. Tactical concessions, including a temporary freeze or caps on uranium enrichment, are unlikely to suffice this time. At the same time, accepting significant concessions such as zero enrichment would be ideologically damaging to the Islamic Republic; the regime has long framed enrichment on Iran’s soil as a symbol of sovereignty and national pride. Limits on missile capabilities — a central component of Tehran's defense strategy — meanwhile, would directly threaten regime survival. As long as Supreme Leader Ali Khamenei remains in office, it is unlikely that Tehran will cross its long-standing red lines. Against this backdrop, Iranian leaders may judge that absorbing a foreign military confrontation carries fewer risks to preserving the Islamic Republic than capitulating under pressure.

From a military standpoint, Iran is not positioned to meaningfully challenge the conventional superiority of the United States or Israel. Still, Iran should not be underestimated. Its strategy rests on asymmetric tools: a sizable ballistic missile and drone arsenal, cyber capabilities, and a network of regional partners capable of imposing costs across multiple fronts. Iran has shown that it can absorb strikes while still imposing costs: During the 12-day war in June, it launched over 500 missiles toward Israel,⁵ with ACLED recording over 40 direct hits in populated areas that killed more than 30 people (see map below). 

Renewed attacks on Iran will likely trigger Tehran to retaliate in ways that significantly raise the price of military confrontation for its adversaries. The underlying assumption of this strategy is that inflicting tangible costs — including US casualties — could generate political pressure in Washington to de-escalate. Iranian officials increasingly interpret their earlier restraint, including after the killing of Qassem Soleimani and US targeting of nuclear facilities, as having failed to deter future pressure. This time, Iran may seek to demonstrate that even limited US or Israeli strikes would carry costly consequences, through missile or drone attacks on Israel, strikes on US bases, maritime disruption, or proxy activity.

At the same time, Iran faces real constraints. Its regional network has been degraded, its air defenses and missile infrastructure damaged, and its capacity for coordinated, high-intensity escalation reduced. Hezbollah, long one of Iran’s most important regional assets, has remained under sustained pressure from the Israel Defense Forces, which has depleted the group’s operational capacity (for more on Israeli military campaigns, see ACLED’s 2026 Conflict Watchlist). Further, more severe retaliatory actions, such as attempting to close the Strait of Hormuz or striking Gulf energy infrastructure, would almost certainly trigger a far more expansive US response. The prospect of a managed escalation, therefore, is fragile: If Iran miscalculates, its regional partners escalate beyond its control, or the US or Israel shows a willingness to push further than Tehran anticipates, the conflict could rapidly expand beyond what any side initially intended.

How could a war reshape internal stability and political dynamics in Iran?

If war were to break out, internal stability would likely deteriorate in the short to medium term as the regime’s already securitized approach toward domestic governance further hardens. The Islamic Republic has repeatedly framed domestic dissent as foreign-backed subversion — and demonstrated its willingness to use significant violence against its own population. During the January unrest, ACLED records lethal force against protesters in more than 140 towns and cities nationwide. A major conflict could intensify this trend. Heightened threat perception would, therefore, likely lower the regime’s tolerance for any form of opposition, accelerate repression, and expand surveillance and coercive controls over daily life. 

Should war lead to rapid regime destabilization, however, the risk of internal instability would be significant. Iran lacks a credible, organized alternative leadership inside the country capable of quickly filling a power vacuum. Such a scenario risks fragmentation, chaos, and violent power struggles, including potential armed conflict among regime factions and existing or emerging opposition groups. It is difficult to imagine that the Islamic Revolutionary Guard Corps would allow the Islamic Republic to collapse without a violent internal contest.

What if the Islamic Republic manages to avoid war?

Not only externally but internally, the Islamic Republic faces a crisis of its own making. Years of mismanagement, corruption, and sustained sanctions have eroded the state’s capacity to deliver economic security, while its restrictive social and political controls have curtailed freedoms. The challenges the regime faces today are the cumulative result of prolonged political inflexibility and a persistent reliance on coercion. 

Even if war is avoided, Iran’s domestic instability is likely to persist. The economic drivers of unrest are not going away. Without a diplomatic breakthrough delivering tangible sanctions relief — which currently looks unlikely — tighter enforcement of existing sanctions, particularly on oil exports, will further squeeze the economy. But the damage goes deeper. The large-scale killings during the January unrest have fractured the social contract to a degree that even if the Islamic Republic were to secure sanctions relief, these gains would not automatically translate into political legitimacy.⁶ Leadership change from within the existing system would not be sufficient either to reverse this trajectory, absent deeper structural or constitutional reform. Avoiding war would not reverse the Islamic Republic’s decline — it will only prolong it.

Visuals produced by Ciro Murillo.