What went wrong with the Iran war?

Michael Green

The author is the CEO of the U.S. Studies Centre at the University of Sydney and the Henry A. Kissinger Chair at the Center for Strategic and International Studies. 

U.S. President Donald Trump has insisted since the Iran war began in February that the United States has already won, has achieved regime change and is close to a diplomatic agreement that will reopen the Strait of Hormuz. Yet opinion polls show that roughly two-thirds of Americans do not believe him. Throughout his career, Trump has relied on instinct and a keen sense of the news cycle. He distrusted experts and consultation, convinced that his confidence alone could carry the day, and at times it did. His operation in Venezuela succeeded in capturing Nicolás Maduro and shifting the balance of influence in the Caribbean away from Cuba, Russia and China. Operation Midnight Hammer also demonstrated U.S. military power, striking Iran’s nuclear facilities without allied casualties, even if its long-term impact on Iran’s nuclear program remains uncertain.

This time, however, Trump’s confidence has left him trapped. A campaign for genuine regime change would require ground forces in a country with twice Iraq’s population and far more difficult terrain, at a time when public support for the war is weak and U.S. stocks of critical munitions are running low. Yet simply stepping back would allow Iran to impose tolls on shipping through the Strait of Hormuz and use the proceeds to rebuild its missile and nuclear capabilities, strengthen proxy forces in Lebanon and Yemen and pursue regional dominance. Such an outcome would inflict even greater damage on U.S. credibility than the current stalemate. Trump has boxed himself into a position with no easy exit.

His mistake was not using force against Iran. Tehran was on course to deploy roughly 10,000 missiles by 2028, enough to overwhelm missile defense systems in Israel and the Gulf. The campaign against Iran’s nuclear facilities was also incomplete. There was therefore a strong case for continuing military operations short of full-scale war to constrain the Iranian threat, a strategy Israelis often describe as “mowing the lawn.”

Trump’s real mistake was believing that airpower alone could bring about regime change. Faced with an existential threat and lacking meaningful leadership outside the hardline Islamic Revolutionary Guard Corps, Tehran resorted to retaliatory attacks on regional energy infrastructure. Once considered too risky, such strikes have become an effective way for the regime to keep pressure on Washington. Trump’s accommodating view of Russian President Vladimir Putin also obscured the danger that Moscow might assist Iran in targeting U.S. forces and facilities.

To Trump’s credit, he has not abandoned the effort. Instead, his administration is pursuing an “escalate to de-escalate” strategy, combining greater military pressure with tighter restrictions on Iranian exports in hopes of forcing Tehran back to the negotiating table. That approach could produce temporary results, but it is unlikely to break the regime’s determination to maintain leverage over the Strait of Hormuz and impose a strategic humiliation on the United States. A more likely outcome is an extended cycle in which military confrontation intensifies, diplomacy resumes while both sides rebuild their military capabilities, negotiations collapse and fighting begins again. Such a pattern could continue for months or even years.

What lessons does this hold for South Korea?

First, attempting regime change through military force alone is extraordinarily dangerous, particularly when it depends primarily on airpower. Deterrence can succeed, but leaders who conclude they have nothing left to lose may resort to what scholars describe as “gambling for resurrection,” embracing high-risk actions in hopes of escaping inevitable defeat.

Second, the United States is unlikely to pivot cleanly back to Asia despite the hopes of many strategists. Perhaps such a shift was never fully realistic. The United States has global interests and global responsibilities that cannot simply be suspended when crises erupt elsewhere. The South Korea-U.S. alliance and other partnerships in Asia must therefore continue coordinating to preserve credible deterrence even as Washington remains occupied by the demands of the Iran conflict and the strain it places on military operations and munitions.

Third, South Korea should take the lead in strengthening solidarity among U.S. allies in Asia and with Europe. The Iran war reinforces a lesson already evident from Ukraine: China, Russia, Iran and North Korea may not be bound by formal alliances, yet they have repeatedly demonstrated a willingness to cooperate far more closely than many expected when confronting U.S. allies. Defense planners should therefore give serious consideration to scenarios in which China, Russia or Iran become involved in a future contingency on the Korean Peninsula.

Finally, policymakers should avoid reducing the challenge posed by Iran or North Korea to a simple choice between diplomacy and war. On the Korean Peninsula and in the Gulf, military strength and credible deterrence remain more important than diplomacy alone. At the same time, diplomacy continues to have an essential role. Managing Iran and North Korea means choosing among bad options rather than good ones. Whether one approaches these problems as a hawk or a dove, there are no easy answers, and simple solutions are unlikely to succeed.