What if war breaks out between the U.S. and Iran? This once-theoretical scenario feels more real than ever as tensions between the two nations hit a boiling point in early 2025. With the Iran nuclear deal (JCPOA) on the verge of expiring, President Donald Trump doubling down on “maximum pressure” sanctions, and Iran advancing its nuclear capabilities at an alarming pace, the risk of open conflict has never been greater. The latest cycle of retaliatory threats—sparked by U.S. airstrikes in Yemen and Iran’s vow of a “devastating” response—underscores how quickly words can turn into action. As diplomacy falters and military posturing escalates, examining the potential fallout of such a war isn’t just speculation—it’s a pressing global concern.
Historical Context of US-Iran Relations
The antagonistic relationship between the United States and Iran did not emerge in a vacuum but is rather the product of decades of mutual distrust and historical grievances. The 1953 CIA-backed coup that overthrew Iran’s democratically elected Prime Minister Mohammad Mosaddegh in favor of strengthening the rule of the pro-Western Shah Mohammad Reza Pahlavi planted seeds of resentment that blossomed during the 1979 Islamic Revolution. The subsequent hostage crisis, where 52 American diplomats and citizens were held for 444 days, cemented the adversarial relationship in American consciousness.
Throughout the 1980s and 1990s, tensions continued as Iran was designated a state sponsor of terrorism by the U.S., while Iranians resented American support for Iraq during the devastating Iran-Iraq War. The relationship deteriorated further during George W. Bush’s presidency when Iran was included in the “Axis of Evil,” despite initial cooperation following the September 11 attacks. The nuclear issue emerged as the central point of contention, with the international community increasingly concerned about Iran’s uranium enrichment activities.
A brief moment of diplomatic breakthrough came with the 2015 Joint Comprehensive Plan of Action (JCPOA), which imposed significant restrictions on Iran’s nuclear program in exchange for sanctions relief. However, President Trump withdrew from the agreement in 2018, implementing instead a “maximum pressure” campaign of harsh economic sanctions. The Biden administration’s attempts to restore the deal ultimately failed, and now with Trump’s return to office, the reinstatement of maximum pressure policies has pushed tensions to new heights1. This historical context has created deeply entrenched narratives on both sides that make de-escalation particularly challenging and increase the risk of conflict.
The Path to Escalation: Current Flashpoints
The path to potential military conflict between the United States and Iran in 2025 is paved with multiple flashpoints that could trigger escalation. Foremost among these is Iran’s nuclear program, which has advanced significantly since the U.S. withdrawal from the JCPOA in 2018. According to recent assessments, Iranian policymakers are now “intensely debating the need to weaponize the country’s nuclear program,” though Supreme Leader Khamenei continues to stress the program’s peaceful nature1. This debate has taken on new urgency as Iran’s regional position has weakened, with Hamas and Hezbollah suffering significant setbacks and the collapse of the Assad regime in Syria.
The Trump administration’s swift reimposition of maximum pressure sanctions upon taking office in January 2025 has further heightened tensions. These sanctions target Iran’s oil sector with the stated goal, according to U.S. Treasury Secretary Scott Bessent, to “collapse its already buckling economy”2. The administration has also ended exemptions previously granted to Iraq for importing electricity from Iran and is pressuring European powers to activate the snapback sanctions mechanism before its expiration in October 20252.
Regional conflicts serve as additional flashpoints. U.S. airstrikes in Yemen beginning March 15, 2025, dramatically increased tension levels. President Trump has directly threatened Iran with “dire consequences” if Houthi attacks on Israeli ships continue, despite Iran’s insistence that it does not control Houthi decision-making4. The resumption of Israeli attacks in Gaza on March 17 has further inflamed regional tensions at a precarious moment2.
In response to these pressures, Iran has significantly increased its military budget, which saw a 200% increase in President Pezeshkian’s first budget since taking office in August 2024. This has been characterized by analysts as a “war budget,” with 47% of Iran’s oil export revenues going directly to the armed forces5. This military buildup, coupled with increasingly threatening rhetoric from both sides, creates a tinderbox where miscalculation or a minor incident could trigger rapid escalation toward full-scale conflict.
Military Capabilities Assessment
Any analysis of a potential U.S.-Iran conflict must acknowledge the significant asymmetry in conventional military capabilities between the two nations. The United States maintains the world’s most powerful military, with unmatched global power projection capabilities, advanced weapons systems, and overwhelming air and naval superiority. In contrast, Iran has developed its military strategy around asymmetric warfare capabilities designed specifically to counter American advantages in the Persian Gulf and broader Middle East.
Iran’s military doctrine emphasizes what military analysts call “anti-access/area denial” strategies. The Islamic Revolutionary Guard Corps (IRGC) maintains a large arsenal of ballistic and cruise missiles capable of targeting U.S. bases throughout the region and potentially striking Israel. Iran’s naval forces, particularly the IRGC Navy, possess numerous small, fast attack craft designed to swarm larger vessels, as well as advanced anti-ship missiles that could threaten U.S. naval assets in confined waters like the Strait of Hormuz.
The IRGC Quds Force has spent decades developing a network of proxy forces throughout the region, from Hezbollah in Lebanon to various militias in Iraq, Syria, and Yemen. Despite recent setbacks to some of these groups, they still represent a significant capability to target U.S. interests across multiple countries simultaneously. This network provides Iran with deniability while extending its reach throughout the region.
What remains the most concerning aspect of Iran’s military capabilities is its advanced ballistic missile program and increasingly sophisticated drone technology. Recent Israeli strikes in April and October 2024 that targeted Iran’s air defenses demonstrated vulnerabilities in Iran’s defensive systems1, but also likely accelerated Iran’s efforts to improve these capabilities. Major General Salami of the IRGC has warned that any threat carried out against Iran would draw a “tough, decisive and devastating reaction”4, language suggesting confidence in Iran’s retaliatory capabilities despite these setbacks.
The U.S. military’s advantages in conventional warfare are undeniable, but Iran’s asymmetric capabilities and regional proxy network ensure that any conflict would not be a quick or clean engagement. The significant increase in Iran’s military budget in 2025, described as a “war budget” by analysts5, indicates that Tehran is rapidly strengthening these asymmetric capabilities in anticipation of potential conflict.
Potential War Scenarios
If war were to break out between the United States and Iran, it could unfold along several different trajectories, each with distinct characteristics and escalation patterns. Understanding these potential scenarios is crucial for assessing the likely consequences and identifying possible intervention points.
The first and perhaps most likely scenario involves a limited conflict triggered by a specific incident—such as an attack on U.S. forces in the region by Iranian proxies, an incident in the Persian Gulf involving U.S. and Iranian naval forces, or an Iranian response to Israeli strikes on its nuclear facilities. In this scenario, the United States might conduct targeted airstrikes against Iranian military assets, command and control facilities, and nuclear sites. Iran would likely respond with missile strikes against U.S. bases in the region and activate its proxy network to target American interests across the Middle East. This limited conflict could last weeks to months, with both sides attempting to calibrate their actions to avoid full-scale war while demonstrating resolve.
A second scenario envisions a more comprehensive campaign initiated by the United States, possibly in coordination with Israel, aimed at severely degrading Iran’s nuclear infrastructure and military capabilities. This would involve extensive air and missile strikes, cyber operations, and potentially limited ground operations by special forces. Iran’s response would likely be more dramatic than in the limited scenario, potentially including attempts to close the Strait of Hormuz, widespread attacks by regional proxies, and possibly direct attacks on Israeli cities. This scenario carries a much higher risk of regional conflagration.
The third and most severe scenario contemplates a full-scale invasion and regime change operation similar to the 2003 Iraq War. Given the lessons of Iraq and Afghanistan, this scenario seems less likely, but cannot be entirely ruled out if certain triggers occur, such as evidence of Iranian nuclear weaponization or a catastrophic attack against U.S. forces or allies. Such a conflict would involve a massive deployment of U.S. ground forces and would likely last years rather than months, with enormous costs in both human lives and resources.
In all these scenarios, the potential for miscalculation is high. According to recent analysis, “Trump and his senior officials should refrain from making counterproductive threats of the use of military force against Iranian nuclear sites,” precisely because such rhetoric increases the risk of unintended escalation6. The Trump administration’s mixed signals about its diplomatic intentions while threatening military action creates a dangerous environment where Iran might feel compelled to take preemptive actions that could trigger a larger conflict.
Human Cost of Conflict
The human consequences of a U.S.-Iran war would be devastating and far-reaching, extending well beyond the immediate battlefields. Even in a limited conflict scenario, thousands of civilians would likely be killed or injured in both Iran and across the region. Iran’s population of over 85 million people, many concentrated in dense urban areas, would be particularly vulnerable to air strikes targeting military and nuclear facilities often located near population centers.
Direct civilian casualties from military operations would represent only the beginning of the humanitarian crisis. Critical infrastructure damage—including power plants, water treatment facilities, hospitals, and transportation networks—would create cascading public health emergencies. The experiences of Iraq, Syria, and Yemen have demonstrated how modern conflicts in the Middle East rapidly degrade essential services and create conditions for the spread of disease and malnutrition.
A war would likely generate massive displacement, potentially creating millions of refugees seeking safety in neighboring countries already struggling with existing refugee populations. Turkey, Pakistan, Iraq, and Azerbaijan would face particularly severe challenges absorbing Iranian refugees, potentially destabilizing these countries and creating secondary humanitarian crises.
The psychological toll would extend for generations. Children exposed to the trauma of war face long-term mental health consequences, educational disruption, and reduced life opportunities. Communities torn apart by conflict often experience increased rates of domestic violence, substance abuse, and social breakdown. The destruction of cultural heritage sites—of which Iran has 24 UNESCO World Heritage Sites—would represent an irreplaceable loss to human civilization.
For American military personnel and their families, a protracted conflict would mean extended deployments, casualties, and the psychological impacts of combat. Veterans of previous Middle East conflicts continue to struggle with post-traumatic stress disorder, traumatic brain injuries, and reintegration challenges—problems that would only multiply in a new, potentially larger conflict.
These human costs extend beyond the direct participants. Regional populations would suffer from economic disruption, increased sectarian tensions, and potential spillover violence. The international community would face increased refugee pressures, humanitarian aid burdens, and the diversion of resources from other global challenges like climate change and poverty reduction.
When considering the question “What if war breaks out between the United States and Iran?”, the human dimension must remain central to any analysis. The cost in human suffering would far outweigh any potential strategic gains for either side, a reality that underscores the critical importance of finding diplomatic solutions to the current tensions.
Economic Consequences
A military conflict between the United States and Iran would trigger severe economic repercussions that would reverberate throughout the global economy. The most immediate impact would likely center on global energy markets, as Iran controls the Strait of Hormuz, through which approximately 20% of the world’s oil supply passes. Any disruption to this critical chokepoint would send oil prices soaring, potentially to unprecedented levels depending on the duration and severity of the disruption.
Even before any actual blockade, the mere threat of conflict in early stages of escalation would trigger price speculation and market volatility. Energy-intensive industries worldwide would face sharply rising costs, and consumers would experience rapid increases in fuel prices and energy bills. Countries heavily dependent on oil imports, particularly in Asia and Europe, would face severe economic pressures.
Iran’s economy, already struggling under the weight of sanctions, would face catastrophic collapse in a conflict scenario. President Pezeshkian’s attempts to provide sanctions relief to Iranians would be completely derailed5. The country’s infrastructure damage would require hundreds of billions of dollars to repair, funds that would be unavailable with Iran cut off from international financial systems. Ordinary Iranians, already experiencing high inflation and economic hardship, would face extreme deprivation.
The American economy would not emerge unscathed. Beyond the direct costs of military operations—potentially running into trillions of dollars over time—the U.S. would face significant economic disruptions from higher energy prices, market instability, and the diversion of resources from domestic priorities. The experience of the Iraq and Afghanistan wars demonstrated how protracted conflicts drain national resources and contribute to fiscal challenges.
Regional economies would suffer severe collateral damage. Gulf states, despite potentially benefiting from higher oil prices in the short term, would face reduced foreign investment, tourism decline, and increased security costs. Countries with close economic ties to Iran, such as Iraq, Syria, and portions of Central Asia, would lose critical trading partners and face potential financial collapse.
The global financial system would experience significant instability, with equity markets declining sharply, particularly in regions most exposed to Middle East instability. Insurance costs for shipping, aviation, and commercial operations throughout the region would skyrocket, further dampening economic activity. Supply chain disruptions, already problematic following the COVID-19 pandemic, would intensify, affecting manufacturing and retail worldwide.
Long-term economic consequences would include the diversion of international development resources toward humanitarian relief and reconstruction, delayed progress on climate initiatives due to emergency fossil fuel exploitation to compensate for Middle East disruptions, and potentially lasting changes to global trade patterns. The economic impact of a U.S.-Iran conflict would thus extend far beyond the immediate participants, affecting global prosperity for years or even decades.
Regional Impact and Involvement
A U.S.-Iran conflict would fundamentally reshape the Middle East’s geopolitical landscape, drawing in regional powers and potentially transforming long-standing alliances and rivalries. Israel, as Iran’s most implacable regional adversary, would likely play a significant role in any conflict scenario. The Israeli government has been actively lobbying the Trump administration to support direct strikes on Iran’s nuclear program1, and would almost certainly participate in military operations against Iran, either overtly or covertly. However, Israel would also face severe security challenges as Iran and its proxies would target Israeli cities with missile strikes. The recent weakening of Hezbollah and Hamas might reduce but not eliminate this threat1.
Saudi Arabia, Iran’s primary competitor for regional influence, would face a complex strategic calculus. While Riyadh might welcome the degradation of Iranian power, it would also be exceptionally vulnerable to Iranian retaliation, particularly against its oil infrastructure. Recent Saudi-Iranian diplomatic rapprochement efforts would collapse, and the kingdom would need to decide whether to actively support U.S. military operations by providing bases and logistical support, knowing this would make it a target.
Turkey, straddling NATO membership and regional independence, would face pressure to allow the use of bases for U.S. operations while managing domestic opposition to such involvement. Ankara would also confront a potential refugee crisis if Iranians flee northward, straining Turkey’s already stretched resources managing Syrian and other refugee populations.
Gulf states like Qatar, the UAE, and Kuwait would become front-line states in any conflict, with their proximity to Iran making them both potential staging grounds for U.S. operations and targets for Iranian retaliation. Their extensive economic ties to both the U.S. and global energy markets would be severely disrupted, potentially undoing years of economic diversification efforts.
Iraq finds itself in perhaps the most precarious position of any regional state, sharing a long border with Iran and hosting both U.S. forces and Iran-backed militias within its territory. A U.S.-Iran war would likely reignite sectarian tensions and threaten Iraq’s fragile stability. The U.S. decision to end exemptions for Iraqi electricity imports from Iran already represents a significant pressure point2.
The conflict would almost certainly spill into Syria, Lebanon, and Yemen, where Iran maintains proxy forces and influence. The recent collapse of the Assad regime in Syria has already altered regional dynamics1, but remaining Iranian-backed elements would likely be activated against U.S. and Israeli interests. In Yemen, the ongoing U.S. bombing campaign against the Houthis that began on March 15, 20252, would intensify, further devastating a country already suffering from years of conflict and humanitarian crisis.
Regional involvement would not be limited to passive impact; the actions of these states would shape the conflict’s trajectory and potentially determine its outcome. Their decisions about basing rights, overflight permissions, intelligence sharing, and diplomatic positioning would create the strategic environment in which the conflict unfolds. The complex web of regional rivalries, sectarian divisions, and competing interests ensures that no country would remain untouched by a U.S.-Iran war.
Global Power Dynamics
A military conflict between the United States and Iran would not occur in isolation but would significantly impact global power dynamics, particularly involving major powers like Russia, China, and the European Union. These powers would view the conflict through the lens of their own strategic interests, potentially transforming what begins as a regional conflict into a global power competition.
Russia would likely provide diplomatic support to Iran and possibly limited military assistance in the form of intelligence, defensive weapons systems, and cyber capabilities. Moscow has cultivated closer ties with Tehran in recent years, seeing Iran as a valuable partner in countering U.S. influence in the Middle East. A prolonged U.S.-Iran conflict would divert American resources and attention from other areas of competition with Russia, such as Eastern Europe and the Arctic. However, Russia would be careful not to become directly entangled in the conflict in ways that might trigger a broader confrontation with the United States.
China, as Iran’s largest trading partner and a significant purchaser of Iranian oil through various sanctions-evading mechanisms, would face difficult choices. Beijing has signed a 25-year strategic cooperation agreement with Tehran but also values stability for its Belt and Road Initiative and broader economic interests. China would likely condemn U.S. military action while continuing to purchase Iranian oil despite sanctions, providing Iran with a crucial economic lifeline. Chinese diplomatic efforts would focus on presenting Beijing as a responsible stakeholder promoting peace while portraying the United States as a destabilizing force, potentially accelerating the ongoing realignment of Middle Eastern countries toward China.
The European Union’s response would be complicated by internal divisions. While European powers share concerns about Iran’s nuclear program, many opposed the U.S. withdrawal from the JCPOA. According to recent reporting, Britain has stated they could initiate the snapback sanctions mechanism to prevent Iran from obtaining nuclear weapons2, indicating some alignment with U.S. policy. However, other EU members might be more hesitant to support military action. European countries would face significant economic consequences from energy market disruptions and would bear the brunt of potential refugee flows. This could create tensions within the transatlantic alliance if European leaders perceive the conflict as avoidable or disproportionate.
International institutions like the United Nations would be largely paralyzed by great power competition, with Russia and China likely vetoing any Security Council resolutions authorizing force against Iran. This institutional deadlock would further erode the legitimacy of global governance structures already strained by great power rivalry.
A protracted conflict could accelerate the trend toward a more multipolar world order, with regional powers seeking greater autonomy from great power competition and potentially forming new alignments based on pragmatic interests rather than ideological affinity. The post-war reconstruction phase would become another arena for competition, with China potentially offering infrastructure investment through its Belt and Road Initiative while the United States focuses on security arrangements.
In this way, a U.S.-Iran conflict would not merely resolve regional tensions but would serve as a catalyst for broader geopolitical realignment, potentially marking a significant inflection point in the international order’s ongoing evolution away from the post-Cold War U.S.-dominated system.
Nuclear Dimensions of the Conflict
The nuclear dimension represents perhaps the most dangerous aspect of potential U.S.-Iran hostilities, as it introduces the risk of unprecedented escalation and regional proliferation. Iran’s nuclear program stands at the heart of tensions with the United States. By early 2025, with the JCPOA set to formally expire later in the year, Iran has significantly advanced its nuclear capabilities. After the U.S. withdrawal from the agreement in 2018, Iran progressively exceeded the deal’s limitations on uranium enrichment levels, stockpile size, and the deployment of advanced centrifuges.
The most alarming development in early 2025 is the ongoing debate within Iranian policy circles about potentially weaponizing the nuclear program. While Supreme Leader Khamenei continues to publicly stress the program’s peaceful nature, the current security environment—marked by the weakening of Iran’s regional allies and direct Israeli strikes against Iranian territory in April and October 2024—has strengthened arguments within Iran for developing a nuclear deterrent1. This internal debate represents a critical inflection point that could fundamentally alter regional security calculations.
In a conflict scenario, Iran’s nuclear facilities would almost certainly be primary targets for U.S. and potentially Israeli strikes. Facilities like Natanz, Fordow, and Arak would face bombardment from bunker-busting munitions designed to penetrate hardened and underground sites. However, the effectiveness of such strikes remains uncertain given Iran’s efforts to disperse, harden, and conceal elements of its nuclear program over many years.
The targeting of nuclear facilities creates special dangers beyond conventional military strikes. Attacks on active nuclear sites could release radioactive material, creating environmental and public health disasters that could affect civilian populations across multiple countries. The Bushehr nuclear power plant, located near the Persian Gulf coast, would be particularly concerning in this regard.
Perhaps the most dangerous nuclear dimension involves Iran’s potential response to an existential military threat. If Iranian leadership believed the regime’s survival was at stake, the incentive to rapidly develop and deploy nuclear weapons would be enormous. This “use it or lose it” pressure could lead to desperate measures, including attempts to assemble crude nuclear devices from existing materials or transfer nuclear technology to proxy groups as an insurance policy against regime collapse.
Regional proliferation represents another critical nuclear risk. A conflict that either demonstrates the vulnerability of non-nuclear states or conversely showcases the deterrent value of nuclear weapons could accelerate nuclear ambitions in Saudi Arabia, Turkey, and Egypt. Saudi officials have previously stated that the kingdom would pursue nuclear weapons if Iran obtained them, raising the specter of a Middle Eastern nuclear arms race.
The nuclear dimensions underscore why armed conflict with Iran carries risks far beyond conventional warfare. As noted in recent analysis, “Absent concrete progress toward an effective deal by mid-2025, there is a real risk that the E3 (France, Germany, and the United Kingdom) move to restore UN Security Council sanctions on Iran that were lifted by the 2015 nuclear deal… Iran’s threat to retaliate by withdrawing from the Nuclear Nonproliferation Treaty (NPT) will only further escalate the crisis”6. Such a withdrawal would remove the last international constraints on Iran’s nuclear program and represent a significant blow to the global non-proliferation regime.
Diplomatic Alternatives
Despite the alarming trajectory of U.S.-Iran relations, diplomatic pathways to avert conflict remain available if pursued with urgency and realistic expectations. Recent reports indicate that President Trump has “consistently expressed support for reaching a nuclear agreement with Iran,” though his administration’s rhetoric sends “mixed signals about U.S. diplomatic intentions”6. This ambiguity must be resolved with clear articulation of achievable diplomatic goals.
A critical first step would be for the Trump administration to distance itself from demands for the “complete dismantlement of Iran’s nuclear program,” which Tehran views as a non-starter6. National Security Advisor Michael Waltz’s recent statements that Iran must “give up their entire nuclear program” or “face a whole series of other consequences” represent precisely the kind of maximalist position that precludes meaningful negotiation6. As analysis of the original JCPOA negotiations demonstrates, progress only occurred after the United States acknowledged Iran could retain uranium enrichment capacity within strict limitations.
For any diplomatic solution to succeed in 2025, it must address core concerns of both parties. For the United States and its allies, this means verifiable constraints on Iran’s nuclear program that prevent weaponization, particularly limitations on enrichment levels, stockpile size, and advanced centrifuge deployment. For Iran, meaningful sanctions relief and economic benefits are essential, along with security assurances that address Tehran’s legitimate defense concerns.
President Pezeshkian, who took office in August 2024, has “promised Iranians sanctions relief, signalling his interest in broader negotiations with the West”1. This suggests a potential opening that could be exploited through direct, high-level engagement. As experts have noted, “It is imperative that the Trump administration moves swiftly to demonstrate it is serious about reaching a mutually beneficial diplomatic deal that prevents a nuclear-armed Iran”6.
The timing for diplomacy is critical. The snapback sanctions mechanism will expire on October 18, 20252, creating both urgency and a potential deadline for negotiations. Given the complexity of the issues and the short timeframe, experts recommend focusing on “quickly implementable measures that maximize transparency and roll back Iran’s most proliferation-sensitive activities, in exchange for tangible benefits to Iran”6.
Regional engagement must complement bilateral U.S.-Iran negotiations. Reducing regional security tensions would “remove a driver of Iran’s threat to weaponize, which could increase the sustainability of any agreement”6. This suggests the value of multilateral dialogue that includes Saudi Arabia, Israel, and other regional stakeholders to address broader security concerns beyond the nuclear issue.
European partners could play a vital mediating role, given their continued support for the JCPOA framework and economic ties with Iran. Their involvement could help build trust and provide additional incentives for Iranian cooperation. International organizations, particularly the IAEA, remain essential for implementing verification measures that would give any agreement credibility.
The diplomatic path is challenging and offers no guarantees of success. However, as the consequences of military conflict become more apparent, the imperative for finding negotiated solutions grows. As a recent analysis concluded, “The best option to prevent this crisis from escalating is to reach an effective, verifiable nuclear agreement”6. The alternative a potentially catastrophic war with global implications makes the diplomatic effort, despite its difficulties, the only responsible course of action.
Long-term Geopolitical Implications
A war between the United States and Iran would fundamentally reshape the geopolitical landscape of the Middle East and beyond for decades to come, creating enduring consequences that would long outlast the conflict itself. The most immediate transformation would occur within Iran, where the nature of the political system could change dramatically depending on the conflict’s outcome. A limited conflict might strengthen hardline elements within the regime, reinforcing anti-American narratives and military influence. Conversely, a more comprehensive conflict could potentially lead to regime collapse, creating dangerous power vacuums and competition among various factions, including ethnic separatists, monarchists, democratic reformers, and military elements.
The regional order established after World War I and modified following the Cold War would face its most serious challenge since the 2003 Iraq War. State boundaries, particularly in countries with significant Iranian influence like Iraq, Syria, and Lebanon, could become increasingly fluid as non-state actors gain prominence in a chaotic environment. The role of external powers in shaping regional affairs would increase, potentially leading to new forms of competition between the United States, Russia, China, and European powers seeking to protect their interests and expand their influence.
The global energy landscape would experience lasting transformation. Beyond the immediate price shocks, a conflict would accelerate the transition away from Middle Eastern oil dependency as consuming nations seek more reliable supplies. This could benefit alternative producers like the United States, Canada, and Brazil while hastening investment in renewable energy as a national security priority. Iran’s vast natural gas reserves, which could have played a significant role in European energy diversification away from Russian dependence, would remain undeveloped or become subject to new international competition.
The international legal order would suffer significant damage from a conflict, particularly if initiated without clear United Nations authorization. The principles of sovereignty and the prohibition on the use of force would be further eroded, creating precedents that other powers might exploit in future conflicts. The non-proliferation regime, already strained by Iran’s actions and the collapse of the JCPOA, would face an existential challenge if the conflict either drove Iran to develop nuclear weapons or inspired other regional powers to pursue their own nuclear programs.
American global leadership would be tested in profound ways by a prolonged conflict with Iran. As seen in Iraq and Afghanistan, the diversion of resources, attention, and political capital to Middle Eastern conflicts limited America’s ability to address challenges elsewhere, particularly in the Indo-Pacific. A new Iranian conflict could accelerate the ongoing rebalancing of global power away from U.S. hegemony toward a more multipolar system where regional powers exercise greater autonomy and great power competition intensifies.
The conflict could also reshape domestic politics in multiple countries. In the United States, war fatigue and potential economic consequences could further polarize an already divided electorate. In Europe, disagreements over supporting U.S. policy could strain NATO cohesion. Throughout the Middle East, popular reactions to the conflict could challenge existing governments, particularly those aligned with the United States.
Perhaps most significantly, a U.S.-Iran war would establish new precedents for how international conflicts are conducted in the 21st century, incorporating cyberwarfare, influence operations, economic weapons, and possibly new military technologies. The lessons drawn from such a conflict would shape military planning, alliance structures, and security frameworks for a generation, potentially inaugurating a new era in international security characterized by greater instability and uncertainty.
Conclusion: Preventing the Unthinkable
As we have explored the potential consequences of a U.S.-Iran war across multiple dimensions—from immediate military confrontation to long-term geopolitical transformation—the overwhelming conclusion is that such a conflict would produce catastrophic outcomes far outweighing any conceivable benefits for either nation or the international community. The human suffering, economic disruption, regional destabilization, and global security implications collectively present a compelling case for exhausting every diplomatic avenue before considering military options.
The current moment represents both danger and opportunity. The danger lies in the escalatory rhetoric, military posturing, and shrinking diplomatic space that could lead to miscalculation and unintended conflict. Recent U.S. airstrikes in Yemen, Iran’s “war budget,” and threats exchanged between officials on both sides create a volatile environment where minor incidents could rapidly spiral into major confrontation245.
Yet opportunity exists in the stated desire of both President Trump and President Pezeshkian to reach an understanding. Trump has “consistently expressed support for reaching a nuclear agreement with Iran,”6 while Pezeshkian has “promised Iranians sanctions relief, signalling his interest in broader negotiations with the West”1. This mutual interest in negotiation, despite the heated rhetoric, provides a foundation for diplomatic engagement.
The window for diplomacy is rapidly narrowing but remains open. With the snapback sanctions mechanism set to expire in October 2025 and Iran’s nuclear program continuing to advance, the coming months represent a critical period for preventing the worst-case scenarios outlined in this analysis2. European partners can play a crucial role in facilitating dialogue, as can regional stakeholders who would bear the consequences of conflict.
For policymakers, the essential task is separating maximalist positions from core security interests. While the complete dismantlement of Iran’s nuclear program might be desirable from the U.S. perspective, achieving verifiable limitations that prevent weaponization would satisfy fundamental security requirements while remaining potentially acceptable to Iran with the right incentives. Similarly, while Iran may desire complete sanctions removal and regional hegemony, basic economic relief and security assurances could satisfy its essential needs.
The lessons of history demonstrate that even the most intractable international conflicts can be managed through skilled diplomacy, as evidenced by U.S.-Soviet relations during the Cold War. What appears impossible during periods of high tension often becomes achievable when leaders recognize the catastrophic alternatives to negotiated solutions. The analysis presented in this article suggests that a U.S.-Iran war would represent a failure of imagination and political will rather than an inevitable outcome of irreconcilable differences.
As citizens, policymakers, and members of the international community contemplate the question “What if war breaks out between the United States and Iran?”, the most important response is to redouble efforts ensuring that this question remains hypothetical rather than historical. The consequences of failure would echo across generations, while the benefits of diplomatic success would create opportunities for a more stable regional order benefiting Americans, Iranians, and the broader international community alike.
