A Red Crescent rescue team on Tuesday works in Tehran near a building that was damaged by a strike.Alaa Al-Marjani/Reuters
Jutta Brunnée is professor of law and university professor at the University of Toronto’s Henry N.R. Jackman Faculty of Law, and a member of L’Institut de Droit International. Stephen J. Toope is professor emeritus of international law at the University of British Columbia and University of Cambridge, and an associate member of L’Institut de Droit International.
In January, Stephen Miller, the U.S. President’s homeland security adviser, set out the Trump administration’s defiant attitude toward international relations. “We live in a world in which you can talk all you want about international niceties and everything else,” he said in a CNN interview. “But we live in a world, in the real world … that is governed by strength, that is governed by force, that is governed by power.”
This version of the “real world” is crass, boiling down to one’s ability to impose one’s will on others. It is also simplistic, reducing complex political issues and all of international relations to a matter of brutal competition.
In his now-famous speech in Davos, Prime Minister Mark Carney invoked this “harsh reality where geopolitics – where the large, main power – is submitted to no limits, no constraints,” calling it a “rupture in the world order.” He urged “honesty about the world as it is.”
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But does realism about “the world as it is” require passive acceptance of material power – economic and military – as the only means of shaping a world order? Do ideas, values and agreed rules have no further role to play? Do we simply accept, for instance, that international law will be discarded when it hinders the unilateral use of force? Is international law “broken,” as The Globe and Mail’s recent editorial argued, because it shields Iran, which oppresses its citizens, threatens its neighbours and perceived enemies, and pursues weapons of mass destruction?
The Iranian regime, as it evolved after the 1979 revolution, is authoritarian, cruel, brutal and dangerous. It has launched attacks in its region, and funded and armed proxy militias and global terrorist organizations. It is fixated on Israel, and has called explicitly for its destruction. It abuses human rights and has violently suppressed the rights of women and minorities within the country. It has resisted efforts to eliminate its ability to produce nuclear weapons.
The U.S. and Israel clearly decided that the moment had come to govern by strength, force and power in launching their war on Feb. 28. But does that mean that all other countries have to just accept the “harsh reality” of geopolitics, necessitating the single-minded pursuit of military ends? Is the international law governing the use of force nothing but mere “niceties”? Is a commitment to the rule of law naive in “the world as it is”?
The answer to each of these questions is no.
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Perhaps counterintuitively, the “real world” requires rules that sometimes constrain the actions of the powerful even when they are pursuing ends that seem justified. Simplistic notions of “realism” obscure profoundly important context and play down the risks of escalation and unintended consequences.
An important part of the wider context around Iran is that war was not the only way to address legitimate fears around Tehran’s military intentions. Back in 2015, Washington and Tehran, along with all members of the UN Security Council and Germany, negotiated an agreement to prevent Iran from further developing nuclear weapons. There was even a framework in place, produced by the International Atomic Energy Agency, to suppress Iran’s nuclear ambitions with intrusive onsite verification. Donald Trump repudiated that agreement in his first term, leaving Iran to proceed with its nuclear program without any international oversight.
From the outset, Israel and Saudi Arabia had opposed any nuclear deal with Iran, believing that even internationally verified promises would not be kept. These countries have long pushed the U.S. to act militarily against Iran, asserting that it was building out its military capacity and increasingly threatening the region.
Barack Obama and Joe Biden resisted this pressure, but Mr. Trump finally yielded in June, 2025, joining Israel in targeted attacks on Iranian nuclear sites. Operation Midnight Hammer lasted 12 days. At the time, Mr. Trump claimed that it had “obliterated” Iran’s nuclear capability. Yet, the continuing threat of Iranian nuclear missile attacks has been deployed as one of many justifications for this renewed conflict.
The unpredictable Trump administration has offered a range of overlapping and competing reasons for the war, revealing an incoherent strategy. At a news conference a few days ago, after claiming that U.S. strikes “totally demolished” military sites on Iran’s Kharg Island, Mr. Trump added that “we may hit it a few more times just for fun.” At the outset of Operation Epic Fury, U.S. Secretary of War Pete Hegseth stated that the American-Israeli attack on Iran was a “war of retribution against the ayatollah and his death cult.” He added that the U.S. would not be bound by anything “international institutions say” or by “stupid rules of engagement.”
U.S. President Donald Trump arrives on Air Force One on Wednesday at Dover Air Force Base, Del., to attend the casualty return for crew members of an Air Force refuelling aircraft who died when their plane crashed in western Iraq while supporting operations against Iran.Julia Demaree Nikhinson/The Associated Press
Unsurprisingly, the ambit and scale of the war have grown rapidly. Beginning with the targeted killing of Iran’s supreme leader and senior military officials, massive assaults were then launched against multiple targets across Iran. Now the war is not limited to Iranian territory, with Tehran quickly escalating the conflict by targeting U.S. regional allies, albeit to relatively limited effect.
While Iran has been able to muster only weak military responses to the U.S.-Israeli bombardment, it has disrupted the global fossil fuel supply chain. In preventing transit through the Strait of Hormuz, Iran has leveraged a powerful pressure point. Ironically, after offering its kaleidoscope of rationales for going to war, the U.S. now seems to be focused on reopening the Strait as a primary goal – one which would not have been necessary if Mr. Trump hadn’t resorted to force in the first place.
Did American decision-makers imagine that the world would have to release 400 million barrels of strategic reserves in an effort to stabilize oil prices? Was it foreseen that the U.S. would lift key oil sanctions previously imposed on Russia, thereby affecting the strategic calculus of a different war? Is the Trump administration entirely comfortable with allowing Iran to replenish its coffers by continuing to export oil?
Meanwhile, the war has expanded on another front, in ways that will produce further unpredictability. Israel has once again attacked the forces of Hezbollah in Lebanon, internally displacing more than 800,000 people. Families from the south of the country now live on streets and in makeshift camps in or near Beirut, which has also been under increasing bombardment.
The risk of escalation and the reality of unpredictability in war are two of many reasons that international law imposes significant constraints on the use of force. Most importantly, wars bring death, serious injury and loss of livelihoods. As we see today, they may profoundly disrupt the global economy. In purely monetary terms, their costs are preposterously high. In the first week of the U.S. action in Iran, the estimated cost was US$11.3-billion – a number that does not include the costs to Israel, Iran, Lebanon or the Gulf states.
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That is why in “the world as it is,” international law demands that states offer clear and legally recognized justifications for war. Yes, at times this may make it difficult to quickly address the threats and abuses of rogue regimes. This constraint is itself realistic. Even for the hegemon, adherence to international law can lower the costs of intervention. It forces focused goals and actions, and facilitates the engagement of allies. Conversely, ignoring international law raises the costs of war. Without clear goals shaped by what is lawful, force almost always escalates. Other states are reluctant to join when there are high risks of unpredictable consequences and they fear undermining the international order. This is all happening today.
For countries like Canada, then, operating within and defending international law represents an important security strategy, too. Restrictions on the use of force create greater predictability, and serve as a bulwark against capricious and unilateral actions by even the most powerful. It is not surprising that the Nordics and Canada, in their March 15 joint statement, declared themselves “united in the view that international co-operation, based on international law, shared values and interests, remains the best way to strengthen our common security and prosperity.”
For true realists, the lesson of the “rupture” in international affairs is that while the hegemon may well be eager to cast aside rules and institutions (at least for the time being), all other states will benefit from insisting on the continuing power of international law to help order our world in predictable and more peaceful ways.