The Realist Case for the Iran War

By Thérèse Shaheen

Tuesday, March 10, 2026

 

It is not too late for the president and his team to be clear about why we did this.

 

The debate about U.S. and Israeli military operations has created a fury of its own. Part of that stems from the lack of sure-footedness by Trump administration leaders and the president himself about why the United States launched the operation. But the United States is acting within well-defined limits and principles of realist statecraft. One might wonder: why now? But that’s quite different from: why?

 

It is obvious to everyone but the most willfully deceptive partisan that the Iranian regime has been an active, aggressive foe of the United States for nearly a half century. The threat Iran poses is not theoretical. President Trump should be explicit that ending the threatening behavior of a dangerous regime is necessary, even if there is no immediate moment that demands it. When abstracted beyond Iran, the broader principle is that sovereignty is not an absolute shield when a regime’s actions have created a high probability of catastrophic harm to others beyond its borders.

 

Whether that regime is causing harm right now (as Iran has for some time, directly and through its proxies in Hezbollah, Hamas, and the Houthis), or if it is “just” a latent threat, is a little academic. Even if the threat were simply prospective, the nature of it is still existential. After all, elimination of Israel and of the U.S. is the regime’s declared policy.

 

Eliminating that threat — to ourselves, and in partnership with Israel, to themselves — is justifiable, even without having a clear sense of what might come next for the Iranian people. The military operation is diminishing the ability of the regime to threaten the U.S. and allies in the region and globally. Curtailing Iran’s ability to do that, even if a government remains that is otherwise unfriendly, is justified. Failing to eliminate the regime may not immediately improve the circumstances of the Iranian people, but the military operation to end the threat to the U.S. includes significant destruction of the internal security apparatus that is harming ordinary Iranians. Life under the mullahs has been decades of repression, torture, and death for many who stayed; exile and separation from their homeland for those who fled. The theocracy has caused untold death and suffering for decades, and the risk for more of that was unacceptably high.

 

Preventing Catastrophic Damage

 

Under extreme circumstances, stopping a regime’s capacity to cause catastrophic damage is justified even if the intervention itself causes serious risk. In the case of Iran, the threat is not speculative. Iran’s intent, capabilities, and behavior have had demonstrably dangerous results for America and Americans. Meanwhile, U.S. actions are not based on dislike, ideology, or rivalry.

 

U.S. military operations have the clear objective to degrade Iran’s capabilities, not to punish. This is a crucial distinction. It is not vengeance or humiliation, but to remove the ability to cause catastrophic harm. These factors are consistent with the accepted elements of a just war, including the right to self-defense and with the intention to establish peace, not for self-interest or aggrandizement.

 

The core justification can be refined this way in more general terms: If a regime’s behavior makes catastrophic conflict likely, then early intervention, though possibly tragic, may prevent greater destruction later. Waiting to act increases the danger. Delay allows capabilities to mature. It is not certain when Iran may have developed a nuclear weapon, but it is reasonable to assume — again, based on intent and prior behavior — that if Iran had such a capability, it would use it.

 

This is not a new concept. The U.S. acted against the Taliban regime in Afghanistan after 9/11 because, as destructive as that day was, the al-Qaeda ability to plan more destructive attacks from inside Afghanistan, and their stated intent to do so, was of immediate concern. Even the initial attacks were intended to be more destructive and may have been if not for the bravery of the passengers on Flight 93.

 

An Exercise in Realism

 

Just the same, one must be cautious to avoid this becoming a justification for endless conflict. The threshold for action should be rare and clearly evidenced. Multilateral recognition is an added constraint. Realist theory and action throughout history can be judged against these precepts. Let’s briefly consider a few:

 

Thucydides, an important theorist of what we call realism today, said that states have a duty to prioritize survival and security. Strategic realities take precedence over moral arguments. One question in this framework is whether the target regime creates structural instability for neighboring states. Does it threaten the balance of power? Does waiting increase the cost of confrontation?

 

In the case of Iran, the answer is yes to all three. By preventing a growing strategic threat, a future catastrophe is averted.

 

In a historic case of practical realism, during the interwar period, Winston Churchill advocated early action against Germany. His position was clear: Such a dangerous regime should be confronted early, or Great Britain and others would pay a price for attempting to appease Hitler in the 1930s. In this case, delay in confronting Germany increased the costs of inaction; waiting proved to be the greater danger. It was unclear what might follow in those early days, but confronting the National Socialists was necessary just the same. If we thought we could stop the spread of communism and the Iron Curtain over Europe and central Asia by not stopping the Nazis, this was flawed thinking.

 

The classic realist theorist Hans Morgenthau might find himself satisfied with action against Iran, too. Core to his thinking was that states must protect national interests and that balancing these against strategic reality is fundamental. He acknowledged the shortcomings of moral absolutism — that war cannot eliminate evil completely. But he was equally concerned with moral passivity: ignoring threats to national interests until they became overwhelming. Morgenthau did grant that post-conflict order is a consideration, particularly as it might alter the relevant balance of power. He understood the role that regional stability played even within the context of great-power confrontation, and he knew that a decision to act would lead to unintended consequences.

 

Even against Morgenthau’s more cautious realism, Operation Epic Fury stands up pretty well. Iran is clearly a destabilizing force in the region, and the balance of regional power can only improve by removing Iran’s ability to conduct offensive operations and destabilize surrounding countries directly or through proxies.

 

There is, of course, the concern of acting against a known threat versus having to deal with the unknown potential consequences. That is the policy risk consideration that President Trump and regional allies have to consider now. Classical realism does not assume that removing a regime will automatically stabilize the balance of power. But the continued existence of the Khamenei regime threatened regional balance for decades. During that time, it expanded its destructive capabilities, directly and through its proxies. There were many times when direct U.S. action to eliminate it might have been justified, beginning with the deaths of more than 241 U.S. military service members in 1983 in Lebanon and several times since. President Trump elucidated these in his announcement of the operation, and he was correct to do so.

 

The risk of continued inaction or limited action by the United States against Iran ultimately exceeded the risk of acting. Leadership in such a circumstance must rely upon prudential judgment and a balance of risks. The duty is to be clear about the rationale, even if it falls short in some ways (e.g., some continuation of authoritarian government in Iran). It is not too late for the president and his team to be clear about why we did this.