The Ripple Effects of Trump’s War on Iran

The death of Ayatollah Ali Khamenei, Iran’s supreme leader, at US and Israeli hands marks a geopolitical rupture on multiple levels that is likely to shake up not only Middle Eastern security and global trade and energy markets, but also fundamental assumptions about the international security order.

Regional Security

Middle Eastern stability will in great part hinge on the degree to which the decapitation of the Iranian leadership leads to a power vacuum or fragmented governance that is exploited by actors seeking to destabilize the area. Many observers have noted that Israeli ambitions, with US backing, to take advantage of a weakened Iran and consolidate regional military dominance could have additional destabilizing consequences. 

Fragmentation of power in Iran would carry serious risks. It could entrench greater militarization in the country and in its neighbors. In the former, rival domestic factions could compete for strategic assets or pursue independent security agendas in the absence of firm central control. Iranian-aligned actors in Iraq, Lebanon, and Yemen might act with greater autonomy, complicating de-escalation. Uncertainty over command-and-control structures could heighten concern about the management of Iran’s missile arsenal. Even perceived ambiguity surrounding the custody and status of nuclear materials could shift threat perceptions and strategic postures.

Trade and Energy 

The Strait of Hormuz is the conduit for roughly 20% of globally traded oil and a significant share of liquefied natural gas (LNG) exports. A sustained closure would likely trigger short-term supply shortages and a sharp spike in oil prices, potentially exceeding previous crisis peaks. LNG prices would also rise steeply, hitting Europe and Asia hardest. Higher insurance premiums for Gulf shipping and longer detour routes would drive up container costs, with price pressures cascading to consumers. Secondary effects could include renewed global inflation and severe strain on energy-importing developing economies in South Asia and sub-Saharan Africa.

International Law

Absent a credible claim of self-defense under Article 51 of the UN Charter or Security Council authorization, the 2026 US-Israeli strikes on Iran stand in direct tension with the Charter’s prohibition on the use of force. In Venezuela, and now in Iran, the United States has shown less inclination to align its actions with established multilateral legal frameworks. In Iran’s case, regime change is an openly declared a strategic objective. Oona A. Hathaway, a law and political science professor, has described the capture of Venezuelan President Nicolás Maduro as the start of a broader “Great Unraveling” of the post-World War II legal order. The Iranian decapitation strike is likely to accelerate the erosion. The cumulative effect will go beyond the contested legality of a single intervention to encompass thinly veiled contempt for the normative guardrails that have structured interstate conduct for decades by the international order's hegemonic guardian.

The justification for intervening in Iran, not on legal but on strategic and ideological grounds, aligns with the principles and world view underpinning the new US National Security Strategy and Secretary of State Marco Rubio’s Munich security conference address weeks before the strikes. Rubio framed US military action not as law-constrained conduct but as necessary leadership in a fractured order. This signals a shift from rule-constrained leadership toward a more overtly power-centric doctrine. Precedents set by this administration could conceivably vindicate and encourage other powers seeking to justify unilateral force. Equally consequential, Washington—and Europe, if it does not distance itself unequivocally from these actions—may see its legitimacy further diminish with partners across the “Global South” already deeply skeptical of Western interventionism and normative integrity. This would have implications for alliance cohesion, strategic hedging, and bloc formation, accelerating a transition toward a more fragmented, multi-vector, bloc-driven world order. 

Might Makes Right

There is no doubt that the Iranian regime is a brutal theocracy that has inflicted domestic and regional havoc for many years. Regardless of the regime’s nature, however, Americans and Europeans must not, explicitly or tacitly, endorse the gradual rise of a global order defined by the survival of the fittest. European leaders who rejoice over Khamenei’s fall risk tacitly legitimizing power, rather than law, as the organizing principle of global security. 

The views expressed herein are those solely of the author(s). GMF as an institution does not take positions.