An Entirely Illegal and Unnecessary War: The U.S. and the Iran War

The war against Iran is not only strategically questionable; it is also clearly illegal under international law. The war further erodes U.S. credibility as a guarantor of the global order.

The war against Iran is rapidly expanding and destabilizing much of the Middle East. What began as a conflict between the United States, Israel, and Iran is now drawing in a growing number of countries across the region. Airports, residential areas, schools, water infrastructure, and parts of the oil industry in Kuwait, Bahrain, Qatar, the United Arab Emirates, and Oman have suffered serious damage. Israel is simultaneously bombing Hezbollah positions in southern Lebanon and appears to be preparing a large-scale ground invasion. More than 700,000 people have already been displaced.

Several NATO countries—including the United Kingdom, France, and Turkey—have become militarily involved, though officially only in a “defensive” capacity. Russia and—more cautiously—China appear to be providing indirect support to Iran. Environmental damage across the region is mounting. Air pollution is rising sharply, and the effective closure of the Strait of Hormuz has sent global energy and raw-material prices soaring. Inflation and falling stock markets are the immediate consequences.

What are Trump’s war objectives?

In Washington, President Donald Trump and Secretary of Defense Pete Hegseth are adopting increasingly belligerent rhetoric. Trump promises swift victory and insists the war will end soon, yet refuses to rule out the deployment of American ground troops. Hegseth announces almost daily that bombing campaigns will intensify further and warns that many more U.S. soldiers may be killed.

Yet the central question remains unanswered: what exactly is the United States trying to achieve? Is Trump seeking regime change and Iran’s “unconditional surrender,” as he has suggested? Or is the objective simply the destruction of Iran’s military capabilities? Either way, a quick end to the war appears unlikely.

As in every war, truth quickly becomes a casualty. All sides operate sophisticated propaganda machines. One of the central claims promoted by the Trump administration is that the war was unavoidable—that Washington had no choice but to strike Iran in order to eliminate an imminent military threat.

An entirely illegal war

This claim does not withstand scrutiny. The bombing of Iran and the killing of Supreme Leader Ayatollah Ali Khamenei constitute actions that clearly violate international law. It is troubling for the future of the international legal order that most European governments - and indeed many other governments around the world - have been reluctant to say so openly. The notable exceptions are the prime ministers of Spain and Norway, who have publicly acknowledged the war’s illegality.

Article 2 of the United Nations Charter explicitly prohibits the use of force against a sovereign state if the aim is to undermine its territorial integrity or political independence. The authoritarian and highly repressive character of the Iranian regime—however terrible—does not grant Washington the legal right to attack the country.

The UN Charter allows only two exceptions to this prohibition. First, the UN Security Council may authorize military action. Second, a state may use force in self-defense if it faces an imminent attack (Article 51).

Neither condition applied here. Iran possesses no long-range missiles capable of striking the United States, which lies more than 10,000 kilometers away. Its medium-range missiles can threaten American bases in the Middle East, as well as Israel and parts of Europe. But there was no credible evidence that Tehran was preparing an imminent attack. A preventive strike was therefore unnecessary. Nor can American self-defense plausibly be invoked simply because a third country—Israel—feels threatened.

The legal situation is also problematic under American constitutional law. The US Constitution and the War Powers Act of 1973 grant Congress the sole authority to declare war. Although presidents have frequently stretched these limits, military force without congressional authorization is permissible only to repel an imminent attack on the United States. The president must notify Congress within 48 hours and withdraw forces after 60 days unless Congress approves the action.

Dubious strategic justifications

The strategic justification for the war is equally weak. Most nuclear experts agree that when the first bombing raids began on February 28, 2026, Iran did not possess an active nuclear weapons program capable of producing a bomb in the near future. After the twelve-day joint Israeli-American bombing campaign against Iranian nuclear facilities in June 2025, Trump himself declared that Iran’s nuclear capabilities had been “eliminated.” Much of the country’s more than 441 kilograms of enriched uranium was buried beneath destroyed facilities, particularly in Esfahan. Moreover, Iran’s uranium enrichment had reached about 60 percent purity—far below the more than 90 percent required for a nuclear weapon.

On March 2, only days after the war began, the director of the International Atomic Energy Agency, Mariano Grossi, confirmed in an interview with CNN that Iran was not close to building a nuclear bomb. The United States was almost certainly aware of this assessment, despite Trump’s statements to the contrary. There are strong indications that Washington’s real objective is to destroy Iran’s missile, drone, and naval capabilities—even though these did not constitute an immediate threat that could justify a preventive war.

Had the negotiations stalled prior to the war?

Equally striking is the fact that diplomatic negotiations were still underway when the bombing began. American and Iranian negotiators had met in Geneva as recently as February 26. Trump’s envoys, his confidante Steve Witkoff and Jared Kushner, his son-in-law, reported that talks had stalled. Yet other participants were far more optimistic. Oman’s foreign minister, Badr Albusaidi, who served as mediator, spoke of significant progress and suggested that a breakthrough might be near. According to Albusaidi, a deal permanently preventing Iran from acquiring nuclear weapons might soon have been within reach.

Continuing negotiations would therefore have been the far more rational course. Contrary to the administration’s claims, there was no imminent threat that required immediate military action.

The war against Iran is thus not only strategically questionable; it is also clearly illegal under international law. It undermines the legal order established by the UN Charter, which has structured international relations for more than eighty years. At a time when global stability already faces immense strain, launching a war without clear legal justification or strategic necessity risks accelerating the further erosion of precisely the international order the United States once claimed to uphold.