Attacking Iran Isn’t Just Illegal, it’s Illegitimate and Dangerous

European leaders should clearly oppose the American and Israeli attacks on Iran. Yet for the most part they have called for more negotiations and condemned Iran. While European leaders may appear to have several good reasons for failing to clearly oppose the attacks – such as recent mass repression carried out by the Iranian government and a desire to avoid antagonizing the Americans – these do not stand up to scrutiny. Supporting, or failing to oppose, an attack on a sovereign state possessing a significant military capability risks further destabilizing the inter-state system as well as causing serious harm to the Iranian population. Instead, European leaders should adhere in both speech and actions to the UN Charter’s prohibition on the use of force.

The American‑Israeli attack on Iran over the weekend clearly violates the prohibition on the use of force, set out in Article 2 of the United Nations charter, which permits force only in collective self‑defense or when authorized by the UN Security Council. Given the dynamics among the five permanent Security Council members, no resolution authorizing an American‑led strike on Iran—explicitly described by the US president as being aimed at regime change—could realistically pass. Moreover, rather than preparing an imminent assault on the United States or Israel, Iran was engaged in negotiations on its nuclear program. The Omani foreign ministry, acting as mediator, reported that Iran expressed willingness to forgo enriched‑uranium stockpiles, accept comprehensive IAEA inspections, and reaffirm its commitment not to develop a nuclear weapon. Even treating Iranian promises skeptically, the IAEA chief continues to state that Iran lacks a structured nuclear‑weapons program.

Beyond Trump’s vague references to unspecified ‘imminent threats’, American and Israeli governments have not seriously tried to give justifications for these attacks that would be compatible with the nations’ legal commitments to uphold the U.N. charter. Instead, President Trump took to social media to claim that these strikes provide an opportunity for the Iranian people to overthrow their unpopular government, while his previous comments had suggest strikes would be a negotiating tactic to extract more concessions from Iran in negotiations. Neither of these justifications would provide a legal basis for attacking another country. Considered in the light of other US and Israeli actions taken over the past year, it suggests that the current governments simply do not care that their actions are illegal.

Despite the clear illegality of the strikes, the international response has followed a consistent pattern. Countries that traditionally align with the United States—such as Canada and Australia—have endorsed the attacks, whereas Germany, the United Kingdom, and France—also US allies—have condemned Iran’s counter‑attack and called for dialogue. This contrast is striking because European governments often emphasize their commitment to international law and previously pushed back when the United States withdrew from the earlier Iran nuclear agreement.

What is missing from European leaders is a clear political argument that the limits on the use of force established by the UN Charter are legitimate and should be respected, even for non-democracies and repressive regimes. The Iranian government’s recent crackdown on protests and mass executions may make attacks on the Iranian government seem like a necessary step to protect the population and usher in a less repressive, more democratic government. However, attacking Iran and seeking to overthrow its government is not a legitimate, legal, or strategically sound way to bring about stable democracy or address the Iranian government’s terrible human rights record.

Reasons Not to Attack Iran

There are numerous good reasons not to support the use of force against other states – even brutal and non-democratic states:

1. Attacking another country without a UN Security Council mandate risks destabilizing the interstate system. For example, the Iranian response to the attacks hit several other countries in the region. Iran also appears to be partially blocking the Strait of Hormuz, which exposes more countries to the effects of the conflict. Furthermore, flouting the Security Council undermines one of the key existing mechanisms to resolve this conflict.
2. Rhetorically supporting attacks on other countries undermines the principle of non-aggression on which everyone’s security relies. Concretely, if the US attacks Iran and European leaders do not condemn this, it becomes much more difficult to ask countries with no geopolitical interest in the fight to bear real costs to support Ukrainian’s right not to be invaded. Furthermore, their own condemnation of Iran for supporting Russia’s invasion of Ukraine will ring hollow. Standing up for the principle of non-aggression here is an opportunity to build diplomatic credibility for core European security interests.
3. Attacking a country causes significant harm to both combatants and civilians. There are credible reports from Iran that a girls school was bombed, killing at least 85 people, mostly children. If this escalates to a broader war, the causalities will certainly not be limited to military personnel and government officials. Furthermore, the harms from destroyed infrastructure, economic damage, and psychological trauma will be borne by an already impoverished and oppressed population.
4. Even if some Iranian citizens – particularly monarchists in the diaspora – are willing to bear the costs of war in hopes of a better future government, attacking or invading Iran is exceedingly unlikely to result in a successful and strong democracy. Both the NATO intervention in Libya to overthrow Gaddafi and the US-led invasion of Iraq serve as clear examples that civil war is a more likely outcome. Physically destroying a government does not imply a transition to progressive democracy, nor something clearly better. There are two central reasons for this. First, American and Israeli governments‘ interests do not align with those of Iran’s democracy movement beyond possibly overthrowing the government. A strong, democratic Iranian state would still likely be seen as a threat to American and Israeli interests in the region. Second, for an attack to succeed the state apparatus must either defect or be destroyed. The Iranian army and the Islamic Revolutionary Guards Corps will not simply disappear because the Americans killed their leaders. It would require a full-scale invasion – like in Iraq – to destroy the underlying institutions and even that might fail. Alternatively, leaving them in place would be a major challenge for building a successful democracy.
5. When countries believe that international law will not protect them, they tend to act aggressively both in domestic and foreign politics. As Vali Nasr shows in his excellent history of Iranian foreign policy, the current Iranian regime can best be understood as a ’national security state.‘ That is, Iranian foreign policy’s central tenant is that Iran is alone, and if attacked, nobody will come to its aid – a world view cemented in the Islamic Republic’s worldview by the Iraqi invasion in the 1980’s. Thus, many of Iran’s aggressive actions in the region, even those that are themselves illegal or immoral, should be understood as stemming from a regime with a paranoid fear of attack and invasion. Blatantly attacking such a regime is likely to lead to more domestic repression and an aggressive foreign policy, not less.
6. The current situation is unlike the humanitarian crises of Cambodia or Rwanda, where a foreign invasion ended, or might plausibly could have ended, mass slaughter of the population. Even in light of the civilian death toll during recent protests, the Iranian government has not yet sought to systematically murder hundreds of thousands or millions of citizens. Furthermore, despite being far weaker than the United States, the Iranian military still has the capacity to resist and to counterattack. Thus, any invasion runs a serious risk of causing much more harm to civilians than the Iranian government itself.
7. Invasions in the name of democracy can put democratic movements around the world at risk. When popular movements are framed by outsiders as a pretext for invasions, governments elsewhere are more likely to see popular discontent or democracy movements not as citizens to be dealt with politically, but as existential threats to national security that must be destroyed.
8. If democratic states act as if the non-democratic states do not have a legitimate right not to be invaded, this will in practice turn into an arbitrary policy of invading countries whenever domestic political forces support it. For example, Saudi Arabia is as autocratic as Iran, but the Saudi government’s rights to protection are being insisted upon as a reason to invade Iran. Democracy indices such as V-dem and Freedom house make quite clear that the majority of states are not fully democratic and many are not democratic at all. Obviously, military intervention against all of them would be a recipe for world war. When democratic states assign themselves the right to decide which non-democratic states are legitimate and worth of the protection of international law, it only gives credence to the widespread perception that rhetoric about democracy is actually just a cover for Western interests.

Given these circumstances and the problems they entail, it is clear that the most morally, politically, and strategically sound course of action available to European leaders is to clearly oppose the American and Israeli attacks on Iran and affirm that the limits on the use of force established by the UN Charter are legitimate and must be respected.