Beyond Epic Fury: The Balance of Power, United States Strategy and Secondary Theatres

CSDS POLICY BRIEF • 8/2026

By Luis Simón

27.3.2026

Key issues

• US engagement in Iran can dilute focus and deplete critical capabilities needed elsewhere, but it may also weaken key nodes in a broader network of adversaries and create indirect advantages vis-à-vis China;
• The balance between tradeoffs and payoffs of engagement in secondary theatres such as Iran or Ukraine is contingent, shaped by the nature and scale of US engagement, the conflict’s duration and intensity, its outcomes, strategic ambition and whether it fragments or consolidates adversarial alignments;
• Allies are central to managing strategic simultaneity. The US cannot sustain high-intensity commitments across multiple theatres alone; greater burden-sharing and regional responsibility are essential to preserving deterrence globally.

 

Introduction

Operation Epic Fury – the sustained United States (US) strikes against Iran – may well be remembered as a tactical success. US and Israeli forces appear to have significantly degraded key elements of Iran’s military capabilities, including parts of its nuclear programme, command and control systems, missile and drone arsenals, navy, defence industrial base and regional proxy networks. Yet the strategic consequences of the war are far less clear.

The Iranian regime has shown remarkable resilience so far. Even in a degraded state, it retains the ability to exploit geography and precision strike capabilities to threaten the Strait of Hormuz asymmetrically – a chokepoint through which a significant share of global energy flows. In other words, tactical success does not eliminate strategic risk.

More broadly, the conflict highlights a recurring strategic pattern: just as the United States seeks to extricate itself from the Middle East, the region has a unique ability to pull it back in. If anything, the Iran war underscores a deeper and enduring problem in US grand strategy: how to manage strategic simultaneity – the need to deter and, if necessary, fight across multiple theatres at once. This challenge, explicitly highlighted in the 2026 US National Defence Strategy, is being stress-tested in real time.

Because US actions in one theatre generate ripple effects across others, the Iran war cannot be seen as just another Middle Eastern contingency. It is a test of how Washington manages global competition in a context of resource scarcity – and what that means for the balance of power. This CSDS Policy Brief examines how the Iran war affects the balance of power and what it implies for US strategy across theatres.

The balance of power today

Students of international relations often turn to the concept of polarity – the number of great powers in the system – to describe the balance of power. Whilst the distribution of power can vary significantly across different domains (military, economic, technological, etc.) and regions, polarity is typically defined as a global property. Great powers are those that can project significant power across all regions and all domains. International systems can thus be unipolar (when there is a clear, dominant great power), bipolar or multipolar. Yet, experts and policy-makers often disagree about how to describe the world they live in.

During the Cold War, the system was widely understood as bipolar. In the decades that followed, it became unipolar, dominated by the United States. Today, however, there is no consensus. Some argue that US primacy endures, others see a transition toward multipolarity; still others describe a more diffuse system in which power is distributed across states, networks and institutions.

Lack of consensus on how to characterise the balance of power today may explain why references to “US-China competition” have gained so much traction in scholarly and policy circles. Yet speaking of bipolarity might be misleading. The United States continues to have the upper hand over the so-called global commons, and thus remains the only country capable of sustained global military projection – a critical benchmark of great power status. That said, China is the only actor with the potential to challenge that position over time. The result is an international system that may not be fully unipolar but is not quite bipolar either – yet, it is increasingly structured around the competition and interaction between these two powers.

In such a system, regional conflicts cannot be treated as isolated events. They are embedded in a broader strategic environment in which local wars can produce global consequences. Indeed, one of the most effective ways to erode the US position may not be through direct confrontation, but by fueling instability elsewhere – encouraging dynamics that draw the United States into secondary theatres and amplify its tendency toward overextension and hubris.

Strategic simultaneity meets resource scarcity

The Iran war highlights a second, more immediate constraint: resource scarcity. Modern warfare consumes high-end capabilities – interceptors, precision-guided munitions, long-range strike systems – at a rate that even advanced economies struggle to sustain. These are not resources that can be rapidly replenished, particularly given the erosion of the US defence industrial base after decades of operating on a war footing.

Even a limited campaign in the Middle East can strain inventories already under pressure from support to Ukraine and preparations for contingencies in the Indo-Pacific. Recent redeployments of US missile defence systems from South Korea to the Middle East illustrate this trade-off in stark terms.

This is the essence of the trade-off problem. A United States deeply engaged in one theatre cannot fully resource another. That creates deterrence gaps and potential windows of opportunity for adversaries elsewhere. Air defence systems deployed in the Middle East are not available for East Asia. Long-range strike assets positioned in the Gulf cannot simultaneously underpin deterrence in the Western Pacific.

Under what is effectively a one-war force construct, dispersion of effort risks becoming dissipation of power. As Churchill warned, the dispersion of strength leads to the dissipation of force. The Iran conflict makes this constraint visible. It highlights that the United States cannot do everything, everywhere, at once – at least not without incurring risk elsewhere.

From trade-offs to payoffs?

But resource scarcity and trade-offs only tell us half of the story. Competition with China is not confined to the Indo-Pacific. It is global. It unfolds across multiple regions and domains, involving networks of partnerships and flows of resources. This means that engagement in so-called secondary theatres can generate payoffs as well as trade-offs.

In Europe, US support for Ukraine held the promise of degrading Russian military power –one of China’s most important strategic partners – and reshaping the broader strategic environment over time. It also held the promise of setting the foundation for a more sustainable US rebalance toward the Indo-Pacific. At the same time, the extent to which those benefits outweigh the diversion of US resources and attention remains contested.

A similar predicament is visible in the Middle East. Despite its emphasis on stockpiling and self-sufficiency, China remains heavily dependent on energy flows from the Gulf. Disruptions to those flows – or increased US leverage over them – could create vulnerabilities for Beijing. Military pressure on Iran may also affect a key node in a broader network of actors that complicate US strategy across regions.

The Iran war thus reveals a central dilemma: engagement in secondary theatres can simultaneously weaken and strengthen the US position in its competition with China. What determines the balance between trade-offs and payoffs is not fixed. It depends on several factors.

First, the nature of US involvement: whether Washington is directly leading operations and expending its own high-end capabilities, or enabling allies to carry the bulk of the burden.

Second, the intensity and duration of the conflict: short, decisive campaigns impose different costs than protracted engagements characterised by sustained burn rates of critical capabilities.

Third, the degree of success: whether operations achieve meaningful degradation of the adversary or become drawn-out contests with limited strategic effect.

And fourth, the level of ambition: whether objectives are limited – such as degrading capabilities – or expansive, such as regime change. The more ambitious the objective, the greater the likely resource consumption and duration, but also the potentially greater strategic payoff if successful.

A fifth factor relates to the degree of cohesion among US adversaries. Engagement in secondary theatres may generate additional payoffs if it exposes fractures within what is often described as an emerging authoritarian bloc. Recent developments suggest that such an alignment may be more limited than often assumed. Neither China nor Russia appears willing to incur significant risk to support Iran directly, underscoring the persistence of divergent interests among these actors. In this sense, US military and diplomatic action can, under certain conditions, weaken not just individual adversaries but also the broader network of relationships that underpins their collective leverage.

These variables interact. A short, allied-enabled campaign with limited objectives may generate net payoffs. A prolonged, US-led conflict with expansive aims may do the opposite. There is no definitive answer. The balance between trade-offs and payoffs is contingent – and evolves over time. This includes not only how resources are used and conflicts evolve, but also how they reshape relationships among US adversaries.

The Middle East in US grand strategy

Nowhere is this tension more visible than in the Middle East. For decades, the region has absorbed a disproportionate share of US strategic attention and resources. The wars in Iraq and Afghanistan – and the Pentagon’s broader focus on counterinsurgency – imposed significant opportunity costs, delaying adaptation to great power competition and allowing others – particularly China and Russia – to leverage the adoption of precision-strike to narrow the military-technological gap with the United States.

Recognising this, successive US administrations have attempted to reduce their footprint in the Middle East. Efforts such as the “Abraham Accords” sought not only to stabilise regional dynamics but to create the geopolitical conditions for a gradual US retrenchment. Yet the Middle East has repeatedly pushed back against US disengagement. Instability has a way of reasserting itself, pulling the United States back in. The rise of the Islamic State complicated earlier efforts to pivot toward Asia. Today, tensions involving Iran and its proxies risk doing the same.

This dynamic is not simply the product of local agency. It is also embedded in broader geopolitical competition. Dispersing US resources across multiple theatres serves the interests of revisionist powers. For China, a United States tied down in secondary regions is a US less able to concentrate power in the Indo-Pacific. For Russia, a similar logic applies. The Middle East, in this sense, is not just a regional theatre. It is part of a broader competitive ecosystem in which instability can be strategically consequential.

And yet, dismissing the region as a distraction would be analytically problematic. Its position as a strategic bridge between Europe and Asia – anchoring maritime routes and underpinning global energy flows – underscores the Middle East’s broader geopolitical significance. The Middle East may not be the centre of gravity of great power competition, but it is a region where relatively small inputs can generate disproportionately large strategic effects – both in terms of trade-offs and potential payoffs.

Part of the challenge lies in the nature of conflict in the region. Unlike Europe and the Indo-Pacific, where the US faces nuclear-armed powers capable of sustained and high-intensity warfare, the Middle East is defined by asymmetry. Iran does not need to match US capabilities to impose costs. Through precision strike, proxy forces and strategic geography, it can threaten key chokepoints such as the Strait of Hormuz. Through a combination of guided rockets, artillery, mortars and missiles, alongside mines and fast attack craft, Iran can continue to generate anti-access effects at relatively low cost. Fully neutralising that threat would likely require not just strikes, but more demanding operations – raids, seizures or sustained maritime control.

Even after suffering military setbacks, Iran retains the ability to disrupt maritime flows and impose economic costs. These dynamics generate second-order effects that extend beyond the region. Disruptions to energy markets, for example, can reshape the broader strategic environment. If oil prices rise above certain thresholds, they may generate windfall revenues for Russia – partially offsetting efforts to weaken its position. In a globally interconnected system, military outcomes do not translate neatly into strategic outcomes. They reverberate across regions and domains.

Europe, the Indo-Pacific and the limits of American power

If the Middle East presents one set of challenges, Europe and the Indo-Pacific present another – and, in some ways, a more similar one. In both regions, the United States and its allies face nuclear-armed adversaries capable of sustaining protracted, high-intensity conflict. The operational requirements differ in detail but increasingly converge in structure: munitions at scale, resilient logistics and the ability to operate in contested environments. This convergence creates opportunities, but also sharpens constraints.

The United States cannot indefinitely sustain the same level of military and industrial commitment across multiple high-intensity theatres. This reality places a premium on allies. Europe will need to assume greater responsibility for its own defence. Indo-Pacific partners will need to do the same – though the United States will likely remain more directly engaged there. The goal is not to eliminate trade-offs. It is to ensure that commitments in one theatre do not undermine deterrence in another.

The debate about US strategy is often framed in binary terms: Europe versus the Indo-Pacific, or global engagement versus regional prioritisation. But this framing is incomplete. The real challenge is managing interdependence – ensuring that actions in one theatre reinforce, rather than erode, the balance of power in another.

The war with Iran brings this challenge into sharp focus. It demonstrates that the United States cannot simply disengage from the Middle East without consequences. But it also underscores the risks of overcommitment and distraction. Strategy, in this context, is not about choosing one theatre over another. It is about navigating trade-offs in a way that maximises cumulative strategic effect.

Conclusion

The United States cannot treat wars in Ukraine, tensions in the Middle East and competition in the Indo-Pacific as separate problems. They are elements of a single, evolving balance of power. The question is not whether regional conflicts matter for global competition. It is how. And more specifically: under what conditions do they generate net strategic advantage or net strategic cost?

The answer depends on the variables that shape the balance between trade-offs and payoffs: the nature of US involvement, the duration and intensity of conflict, the degree of success, the level of ambition and the extent to which conflicts fragment or reinforce adversarial alignments.

The challenge for Washington is not to eliminate trade-offs. It is to navigate them, to ensure that actions in one theatre reinforce, rather than undermine, its position in another. Not all theatres matter equally. But all of them matter. And in a world of strategic simultaneity, the ability to manage their interaction may be the ultimate measure of success.

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