What Are the Unintended Consequences of the U.S.-Iran Conflict for Defense and Security?

The announcement of a conditional, two-week ceasefire between the United States and Iran offers an interlude from an intensive campaign that saw extensive damage to Iran’s military and other infrastructure as the result of coordinated U.S. and Israeli strikes. The conflict’s repercussions have rippled regionally, resulting in impacts across the Middle East, and globally, as Iran leveraged its chokehold on the Strait of Hormuz to inflict pain on economies across the world.

In this Experts React, the CSIS Defense and Security Department, along with other CSIS experts, look beyond the immediate implications of this conflict to explore its unintended consequences, including the long-term risks—and opportunities—that these might bring.

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Pushing Iran Toward Greater Use of Hybrid Threats

Nikita Shah, Senior Fellow, Intelligence, National Security, and Technology Program

Though the United States and Israel may declare a military victory against Iran, their campaign has risked shifting Iran’s primary means of engagement away from military activity and toward greater use of hybrid threats. Comprising the likes of assassinations, cyberattacks, sabotage, psychological operations, and economic coercion, hybrid threats give Iran an asymmetric means of sustaining costs on adversaries alongside conventional military activity. And Iran has a notable track record in hybrid threats, too, across the Middle East, Europe, and, more recently, the United States, serving to project its global reach. This shift will therefore play into Iran’s hands nicely: The Iranian state has an extensive network of proxy actors at its disposal that are willing and able to conduct these types of attacks on its behalf, and who exist in both the physical and digital domains.

One critical consequence of this is displacing the threat away from the military battlefield into the civilian space—specifically, into areas where U.S. vulnerability is high. The conflict is unpopular with a divided U.S. domestic population, exacerbating the United States’ vulnerability to Iranian information operations, where Iran is a skilled operator. The rise of lone-wolf actors in the terrorism landscape makes it harder to defend against Iran-linked actors or individuals radicalized by the current conflict. And Iran could further export its use of criminal actors to conduct targeted attacks (as it has done recently in Europe) against the United States, having previously attempted assassinations on U.S. soil. It therefore comes as no surprise that a Department of Homeland Security (DHS) intelligence assessment in February this year labelled Iran and its proxies a “persistent threat” to the U.S. homeland.

Where the United States is especially vulnerable is in cyberspace. Despite a show of force using offensive cyber capabilities to support the initial air strike campaign against Iran, the United States has left its backyard wide open from a cyber defense perspective. In the current DHS shutdown, the agency responsible for defending against significant cyber incidents, the Cybersecurity and Infrastructure Security Agency (CISA), is reportedly at around 38 percent of regular staffing levels. This is on top of sweeping cuts to CISA personnel, gaps in vital leadership positions, cuts to information-sharing resources, and lapses in cyber legislation that have taken place over the last year.

Part of Iran’s playbook is to raise the cost to countries participating in conflict against it by targeting their citizens and businesses via cyberattacks. This is already taking place, including through disruptions to U.S. critical infrastructure, U.S. medical supplier Stryker, Lockheed Martin, county IT systems in Indiana, Israeli companies, and other countries linked to the conflict. There will inevitably be more victims of cyberattacks in the coming weeks and months; Iranian intent to disrupt will be high, and important domestic moments lie ahead, such as the midterm elections—which Iran has a track record of penetrating, and where state officials recently expressed their concerns about potential disruptions. Against a regime with a deep-rooted desire to impose costs on its adversaries, the U.S. campaign risks making America—and its allies—less safe than before the conflict.

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Data Is a Source of Advantage and Vulnerability in Contemporary Warfare

Emily Harding, Vice President, Defense and Security Department; Director, Intelligence, National Security, and Technology Program

This conflict has highlighted data’s centrality to warfighting. For the last four years, the rest of the world has watched the Ukraine war and wondered if its tech-forward approach to warfare would be the new way of war or specific to that conflict. The answer is now clear: In a different part of the world, with different combatants and different goals, data, AI, and drones have proven critical to battlefield success. This way of war is here to stay.

However, it has also proven data to be a new and significant vulnerability, especially for technology companies. Ukraine wisely moved its national data off-shore in the early days of Russia’s full-scale invasion, a step that was vital to Ukraine’s resilience, despite massive cyber and kinetic attacks from Russia. Although Russia was willing to destroy civilian infrastructure inside Ukraine, it did not go after data centers in neighboring NATO nations. Iran has no such compunction. It has explicitly targeted data centers across the Gulf, inflicting damage and disruption at centers in the United Arab Emirates (UAE) and Bahrain. Strikes on data centers serve a triple purpose: They hurt the regional economy, they potentially disrupt the U.S. military’s A.I.-driven warfighting, and they send a message to the United States that companies like Amazon Web Services (AWS), Microsoft, and other cloud providers are now strategic targets.

This provides food for thought for these companies’ risk calculus. Several times during the fight, the Islamic Revolutionary Guard Corps directly threatened to target U.S. tech companies (including AWS, Nvidia, Apple, Google, and Microsoft). While these companies are willing to expend significant resources to protect their facilities, local laws prohibit private entities from deploying their own air defense or electronic disruption capabilities. That leaves a choice: Can host governments use limited resources to defend these centers? Or should the United States read these threats as attacks on U.S. sovereignty?

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Raising the Risk of Terrorism

Daniel Byman, Director, Warfare, Irregular Threats, and Terrorism Program

The U.S. and Israeli attacks on Iran have increased the short-term risk of international terrorism from Iran and groups like the Lebanese Hezbollah. Just as Tehran sought to widen the war by attacking U.S. partners in the Gulf, conducting or supporting terrorist attacks on the United States and its allies is a way to increase the pain felt by Iran’s enemies. Especially if the conflict begins again, Tehran may believe that additional pain is necessary for the United States and Israel to stop attacks. Even after a ceasefire, Iran may also seek revenge: It has plotted attacks to avenge the killings of senior leaders in the past, and the scale of the recent leadership killings, which include numerous senior regime officials, dwarfs past losses. Finally, the war is inspiring anti-Israel and antisemitic attacks that are not directly tied to the Iranian government.

Iranian attempts to conduct terrorist attacks may fail and, if successful, could easily backfire. The United States and Israel have long prioritized countering Iranian counterterrorism, and their deep intelligence penetration of Iran’s leadership and networks may mean they also have a handle on Iranian terrorist networks overseas. A terrorist attack on the United States might also create the public support for the strikes on Iran that is currently lacking. Similarly, if the attack occurs on an ally’s territory, it might make its leaders and people more hostile to Iran and more willing to support U.S. and Israeli efforts.

A reduction in the terrorist threat over the long term may also be possible. At the very least, both Iran and some of its proxies, notably Hamas and Hezbollah, have been hit hard, and they may not be eager to risk further blows by conducting terrorist attacks on their enemies.

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Consolidating International Alliances Against Iran

Eliot Cohen, Arleigh A. Burke Chair in Strategy

The United States’ longer-term relationships with other Gulf partners—especially Saudi Arabia, the UAE, Qatar, and Kuwait—could take a hit in unanticipated ways. They’ve all been attacked—psychologically as well as physically—and many of the United States’ friends in the region are shocked right now. The United States has a large military presence and many commitments across the Gulf Cooperation Council, foreign military sales and direct commercial sales in the region, and large tech investments and financial deals with Saudi Arabia’s Public Investment Fund, Abu Dhabi’s Investment Authority, and Mubadala (one of Abu Dhabi’s sovereign wealth funds). It is conceivable that the United States could enter a world in which these states change their strategic orientation away from the United States and perhaps lean more toward China, with whom they all have economic ties.

More likely not. Iran attacked a number of its neighbors who gave clear indication that they wanted to stay out of this war. It did so in ways calculated to be the most threatening to them—by attacking oil production and even desalination plants. The logical conclusion for Gulf states is that Iran has adopted a posture of unrelenting threat toward them, which it may even believe will work. Worse yet, Iran has indicated its desire to keep its hands on the throat of Gulf oil shipments by claiming the right to control the Straits of Hormuz—in violation of international law and the vital interests of these states.

For Gulf countries, the United States may not be the ideal ally to deal with an Iran willing to do such things and make such claims, but it is certainly the best one available, in addition to Israel. Israel has proven, in this region, at any rate, to be a military peer of the United States in terms of the ability to deliver precision fire power, provide intelligence, and build defensive systems. China and Russia either cannot or will not offer such protection. This may not result in new formal alliances, but relationships are more likely to consolidate with the United States, Israel, and Ukraine than anyone else. That is not what Tehran expected in this war, and certainly not what it wishes.

One of the most interesting unintended consequences will probably be massive investment by Gulf states in the Ukrainian defense industry. Ukraine has deep, painful experience attempting to fight off drone and missile attacks and is ready to provide relevant equipment and expertise to Gulf nations. This can bring needed revenue to Ukraine to help it stay ahead of the Russian military, and it helps Gulf nations protect their infrastructure. But it also will help with the already dramatic expansion and development of one of the most sophisticated military industries in Europe. Ukraine has led the way into this future of small and cheap platforms and rapid innovation and adaptation. Ukraine is now also a world leader not only in some of the less expensive technologies but in the art of integrating them with higher-end systems such as Patriot. The combination of Ukrainian, Israeli, and American military and technological expertise with Gulf financial resources could be a surprisingly positive outcome of this war.

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Russia Benefits from the United States’ Split Attention

Kateryna Bondar, Fellow, Wadhwani AI Center

The U.S.-Iran conflict has delivered Moscow a set of near-term strategic gains that complicate Washington’s security calculus across theaters. Most immediately, it creates strategic space for Russia to regain initiative in Ukraine. As U.S. military attention, intelligence bandwidth, and munitions have been partially diverted to the Middle East, Western focus and political urgency around Ukraine have weakened, allowing Russia to intensify operations and shape the battlefield on more favorable terms. At the same time, higher global energy prices are boosting Russia’s war economy. Russia could accrue between $45 billion and $151 billion in additional budget revenues in 2026—revenues that directly underwrite Moscow’s war machine in Ukraine. Temporary easing of sanctions pressure further reinforces this effect, undermining a central pillar of U.S. strategy: sustained economic restraint of Moscow.

Yet these gains carry longer-term risks. The conflict accelerates the consolidation of a loosely aligned Russia-Iran-China axis, deepening operational linkages and enabling the circulation of battlefield lessons, technologies, and tactics across theaters. This reinforces adversary adaptation and increases the complexity of future conflicts. Meanwhile, expanded U.S. engagement in the Middle East risks perceptions of strategic overextension, potentially weakening deterrence credibility in Europe. The unintended consequence is not only that Russia benefits in the near term, but that the conflict contributes to a more contested, multipolar security environment in which U.S. resources, attention, and alliances are increasingly strained.

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Transatlantic Cohesion Under Pressure

Jonathan Burchell, Visiting Fellow, Europe, Russia, and Eurasia Program

The U.S.-Iran conflict puts further pressure on transatlantic alliance cohesion. The United States launched strikes without consulting NATO partners, leaving European governments to face difficult domestic questions about the degree to which Washington’s action exports consequences to allies. European public opinion on Middle East military intervention is deeply skeptical. A conflict that was not collectively decided risks becoming a conflict that is collectively paid for—in the form of security challenges, refugee flows, and economic disruption.

Europe must also reckon with the strategic attention problem. A United States managing operations in the Middle East makes it much harder to sustain support for Ukraine and to maintain pressure on Russia. The United States has depleted its stockpiles of air defense interceptor missiles, which has led to reporting that European orders for Ukraine through the Prioritised Ukraine Requirements List (PURL) initiative will be diverted as a result. This will raise further questions about the reliability of the United States as a security guarantor, which could accelerate the push for European strategic autonomy and the imperative for Europe to boost its indigenous defense production.

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The Strait Reveals U.S. Naval Weakness

Mark Cancian, Senior Adviser, Defense and Security Department

Closure of the Strait of Hormuz for five weeks has been unexpected. Iran has done to the U.S. Navy what Ukraine did to the Russian navy: exert control over a key waterway without the ships and aircraft of a conventional navy. The immense power of the U.S. Navy has been rendered impotent in this key mission. This is a glaring failure in a war that militarily has gone well otherwise, such as through rapid establishment of air superiority, effective though not perfect air and missile defense, and superb combat rescue of downed aviators.

Although the administration insists that everything is going according to plan, it’s impossible to believe that this plan included protracted Iranian control of the strait with all the negotiating leverage that entails. The delayed movement of Marines and paratroopers to the region shows a lack of preparation. This naval failure is astonishing because the U.S. Navy has been thinking about this problem for 45 years, ever since the tanker wars of the 1980s. As a young Marine officer, I participated in amphibious planning exercises to capture Qeshm island. Failure in the strait has pushed the administration to threaten Iranian power plants, bridges, and oil facilities as its remaining escalatory tool. The war is now paused and much could still happen, but this naval failure has undermined the administration’s repeated efforts to get a favorable settlement.