U.S. President Donald Trump delivers remarks at the Roosevelt room at White House in Washington, US, Jan. 21, 2025. 鈥 REUTERS

By Marc Champion

US PRESIDENT Donald Trump never did explain to Congress or anyone else what his justifications and goals would be for attacking Iran. Now, with 鈥淥peration Epic Fury鈥 underway, we know. The answer was 鈥渆verything,鈥 making this a gamble on a scale way beyond anything even this former casino owner has done before.

Setting out goals for military action determines why it is needed, how it will be done, and what is the measure of success. In the eight-minute address Trump posted on Truth Social, he laid out at least half a dozen reasons for going to war, starting with the prevention of an imminent threat to the US, of which 鈥 with nuclear negotiations due to resume next week 鈥 there was none.

He followed up with a string of other motives for this major attack: It would eliminate for good Iran鈥檚 nuclear program; destroy its missiles and the production lines to make them; crush its military and ability to support proxies abroad; annihilate its navy; avenge Iranian attacks on US servicemen over 47 years; and halt the Islamic Republic鈥檚 further slaughter of its own people.

Yet the most ambitious goal, and the one that must be achieved to make sense of all the others, was regime change. Without that, the Republic and its activities can be weakened, interrupted, or delayed, but not stopped. Its missiles, nuclear program, domestic repression, and military activities abroad would revive, only now with lessons learned and in a state of war.

Without change at the top, many of the problems Trump and Israel set out to resolve would only be made more difficult. Iran鈥檚 leadership would, for example, almost certainly kick out international nuclear inspectors, radically reducing the ability of the US and others to track Iran鈥檚 uranium enrichment.

Of course, if Trump succeeds in forcing the regime鈥檚 downfall, all will be forgiven and his triumph would be indisputable. That outcome came a step closer with Iranian state television鈥檚 confirmation on Sunday of Supreme Leader Ayatollah Ali Khamenei鈥檚 death. He and the aging revolution he embodied had little support at home and still less abroad. His regime has nothing to recommend it, and the world would 鈥 without question 鈥 be a better place with it gone. For those dismissive of the value of genuine democracy, Khamenei鈥檚 Iran should be an abject lesson.

The risks involved in this operation are, nonetheless, all too real. The moment he launched such a large attack with unlimited goals, Trump incentivized the regime in Tehran to use every means at its disposal to strike back in what it must now treat as a fight for survival. The only question is how much damage it will prove capable of inflicting on the US and its allies, and for how long.

It will take a little time before we know how much of the Iranian leadership, in addition to Khamenei, the initial US strikes killed. Likewise, we can鈥檛 say yet whether US and Israeli jets and missiles were able to destroy enough of Iran鈥檚 ballistic missile launchers to remove any significant threat to American military bases and personnel abroad. Initial explosions were reported in Bahrain, which hosts the US Fifth Fleet, as well as in Dubai. Israel declared a state of emergency as approaching missiles were detected.

Also unknown is what Iranian capabilities will remain to carry out its threats to close the Strait of Hormuz, to sink oil tankers, or to strike the lightly defended oil infrastructure of US Gulf allies. Those dangers explain the reticence of Saudi Arabia, the United Arab Emirates, and other Sunni Arab states with no love for Tehran, to support, let alone participate in, the US-Israeli assault.

If air strikes alone can achieve regime change anywhere, Iran is a good candidate. Khamenei, his ruling elite, and the Islamic Revolutionary Guard Corps (IRGC) that protect them have exhausted their competence to deliver even basic solutions to the state鈥檚 economic failures, and have lost touch with the country. Only weeks ago the IRGC killed thousands, if not tens of thousands, of their own people to cling onto power. These men are the enemies of their citizens.

And yet, there are no precedents for toppling a regime using solely air power. Hence Trump鈥檚 appeal to the Iranian people to rise up and take control. It all now depends on them. Even then, should the Islamic Republic fall, the impact on Iran and its neighboring states might only have begun. This is a country of 92 million people, with a long and proud history, but also no organized domestic opposition ready to take charge and large minorities that may well seek to take advantage of the chaos.

Indeed, a Feb. 22 announcement by five Kurdish Iranian groups to form an Alliance of Political Forces in Iranian Kurdistan has caused immediate concern in Turkey. Kurds 鈥 with a population of 30-plus million spread across Iran, Iraq, Syria, and Turkey 鈥 are among the largest ethnic groups in the world to have no state of their own. This would be a rare opportunity and the temptation to seize it would be great.

The US has been here before: in Afghanistan for 20 years, in Iraq from 2003, and in Libya in 2011, to name just a few instances where its military interventions in the Middle East failed. That does not mean it can鈥檛 work this time, but one thing is certain: There is nobody in Washington who can be sure of where this war of choice leads.

BLOOMBERG OPINION