For two decades, hawkish voices in Washington have called for the United States to attack Iran’s nuclear program. And for two decades their calls have been rejected. That is because for most of that time, the argument against military action was compelling and straightforward. Iran’s nuclear capabilities were immature. The international community was united on the need for Tehran to prove that its nuclear intentions were entirely peaceful and thus was reasonably united in sanctioning the country when it became clear that they weren’t. These sanctions imposed high costs that pushed the Islamic Republic into negotiations.
There are still many good reasons to not bomb Iran. Striking the country would inject more chaos and instability into the Middle East. It would consume substantial American resources at a time when Washington wants to focus on other regions. It could undermine U.S. credibility if the attacks don’t succeed. And the odds of failure are high: even the most accurate strikes might only delay Iranian nuclearization. The best, most durable solution to the issue remains a diplomatic agreement.
But today, the case against military action is not so neat. Iran’s nuclear program is no longer nascent; in fact, the country has just about everything it needs to make a weapon. Tehran, meanwhile, is more vulnerable and more in need of a new deterrent than it was a few years ago: its network of partners is in tatters, and Israel struck targets within Iran’s borders several times in 2024. The international community is also now fractured on whether to pressure the Iranian regime. There are still harsh sanctions on Iran, but they are constantly being breached by China, India, and Russia, among others. Resuming full enforcement may be possible, but it will require China’s cooperation in particular at a time when Beijing faces bipartisan hostility from Washington. Russia’s relationship with Iran is likewise stronger than it has been for decades, buoyed by mutual defense ties. Tehran’s incentives to go nuclear have hardly ever been greater, and its expected costs have likely diminished.
Given the risks of military action, the United States must make a final, good-faith attempt to negotiate a halt to Tehran’s nuclear program early in the Trump administration. But unless it is prepared to live in the world that Iranian nuclear weapons would create, it may have little choice but to attack Iran—and soon. Prudence demands that Washington both plot out military action now and ensure that Iran understands that this threat is real, even as it tries the diplomatic path once more.
CONS OF CONFLICT
There are many reasons to give diplomacy a final chance. First and foremost, American officials do not know whether a military attack would succeed. The United States and its partners may possess the means to destroy all of Iran’s main nuclear facilities. But that is no guarantee of eliminating all the country’s nuclear material, or indeed all of its nuclear equipment, some of which could be hidden away in deeply buried storage. Tehran could, either in anticipation of or in quick response to U.S. strikes, divert some of its of highly enriched uranium to secret sites, preserving enough material for the country to produce multiple bombs quickly.
If Iran were attacked by a declared nuclear power—a designation that applies to the United States—Tehran would be newly incentivized to develop its own deterrent and could perceive that it had more international legitimacy to do so. And with enriched uranium still in hand, it would already possess the main ingredient. The essential elements of bomb-making are known to Iran, and so it would be positioned for fast assembly. That is why the 2015 nuclear deal, or the Joint Comprehensive Plan of Action (JCPOA), focused on preventing nuclear material acquisition rather than on weaponization equipment or missiles.
In fact, Iran’s decades-long development of nuclear expertise means that the country could build a weapon even if military strikes render all of its existing equipment and material unusable. Restoring its nuclear program would take time, but an attack that destroys Natanz and other sites is not the end of the problem any more than was the death of Iranian physicist Mohsen Fakhrizadeh, in 2020, or the attack on Iran’s centrifuge production site, in 2021. The bombing of the Osirak reactor in Iraq, in 1981, did not end its nuclear program; Iraq’s nuclear weapons program even intensified in the following years. The bombing of the al Kibar reactor in Syria, in 2007, may have been more successful, but the country’s plunge into civil war makes it hard to assess the long-term effects of the strike on its nuclear decision-making.
The high costs of attacking Iran mean the United States should again try diplomacy.
To permanently quash Iran’s nuclear aspirations, the United States may have to attack Iran in perpetuity or carry out a much larger assault—one that takes out elements of the country’s security forces or regime. Both tasks would be far longer and more arduous than a limited campaign, and it is foolhardy to assume that Washington has the commitment needed to complete either. This means that strikes on Iran would raise credibility problems for U.S. leaders, especially if Washington eventually gave up its attacks and Tehran produced a weapon.
Moreover, once strikes began, it is hard to imagine there would be a swift turn to diplomacy, short of a change in the Iranian government. Regime change itself is no guarantee of a better outcome, with regard to either the nuclear program or the regime’s other malign activities. Even if the Islamic Republic collapsed, it might only be replaced by a more virulent regime. Iran could descend into anarchy. Few would lament the end of the country’s current government, especially those who have been repressed by it for 40 years. Yet there is a reason why Iranians are also worried about the risks of regime instability and have been since witnessing the Arab Spring.
No matter the outcome, attacks on Iran would strain U.S. resources. Dire reports already abound concerning U.S. ammunition and missile defense interceptor shortages. Additional expenses would come at a poor time for Washington. The international situation today is complex. Russia continues to wage war against Ukraine. There is a risk that China will invade Taiwan. And almost the entire Middle East is unsettled. A new military campaign against Iran would especially burden the United States if Europe, the global South, and Washington’s Arab partners were against or at best skeptical of American military action—which they all may well be.
DEALMAKING
The high costs of attacking Iran mean that the United States should again try diplomacy. And there are reasons to be optimistic that, despite the volatile situation, the two countries can reach an agreement. Diplomacy, after all, has a successful track record when it comes to slowing Iran’s nuclear aspirations. The European initiatives of the early 2000s led to short-term suspensions of Iranian nuclear activities and, when these failed to take root in the long term, compelled Russia and China to support UN sanctions. In 2013, the Joint Plan of Action halted Iranian nuclear advances to allow two years of negotiations that resulted in the JCPOA. The JCPOA outright froze significant parts of Iran’s nuclear program while subjecting it to more stringent international monitoring.
Each of these initiatives eventually failed. But although Iran was responsible for the end of the European-negotiated suspension agreements, Tehran complied with the JCPOA, a fact that even the first Trump administration acknowledged in its mandatory reports to Congress on the deal. The JCPOA collapsed because President-elect Donald Trump withdrew from it in his first term. But Trump is well positioned to engineer a replacement precisely because he killed the last deal. Talks to return the United States and Iran to full, mutual compliance with the JCPOA in 2021 and 2022 died because the Iranians did not trust the United States to live up to an agreement after a transfer of power and because the United States refused to consider other diplomatic approaches. Yet if Trump himself agrees to a new deal, Iran may believe that it will stand. Most Democrats have been supportive of diplomacy, and if Trump gets on board, Republicans might as well.
Although a deal is possible and preferable, coming up with one will be hard. Trump has shown interest in what he describes as a “simple” deal to deny Iran nuclear weapons, but the terms of any deal would have to be complex to have much effect. Tehran and Washington would need to come to terms on how far the constraints on Iran’s nuclear program must go, whether to create rules regarding Iran’s regional behavior, and what sanctions relief and security assurances Iran might receive. Figuring out all these issues would require extensive negotiations—especially to ensure that a deal is sustainable, verifiable, and enforceable—and would require more parties to be involved if regional issues are to be a focus. Multilateral talks are difficult at the best of times. Russia’s war in Ukraine and tensions between Beijing and Washington are just two irritants that would make such a process very difficult to orchestrate today.
FIRST STRIKE
Still, there is reason to hope that, with enough time and creativity, Tehran and Washington can come to some kind of agreement. But despite Iran’s strategic setbacks and vulnerabilities, primarily a result of Israel’s attacks on Tehran’s proxies and on Iran itself in October, Iran’s nuclear progress has made time a resource in short supply. If the United States pursues a “maximum pressure” approach to soften Iran for later talks, Iran could retaliate by hiding its nuclear material, building a bomb, withdrawing from the Nuclear Nonproliferation Treaty, or all three. Should attempts to strike a deal fail, the United States must be willing to use its military.
Iranian nuclear weapons would not present a near-term existential threat to the United States. Washington’s own nuclear armaments would vastly outnumber any Iranian stockpile, and Iran is still developing its intercontinental ballistic missile capability. If Iran were to develop nuclear weapons, however, it would encourage others in the Middle East to do so as well, producing future arms races that risk nuclear war. Even if Iran did not transfer nuclear weapons to proxy groups—although Iran’s decision to equip the Houthis and Hezbollah with ballistic missiles makes a nuclear transfer seem more plausible—its nuclear arsenal could become a target for terrorist or criminal groups. And many U.S. partners would fall within Iran’s range of fire, as would an appreciable supply of the world’s energy resources. A world in which Iran possesses nuclear weapons would thus be a far more dangerous one for the United States and its partners.
Attacking Iran’s nuclear program would come with strategic benefits beyond just preventing a dangerous adversary from going nuclear. Strikes, for example, would further stretch Tehran’s already limited resources. The country, set back again, would struggle more than ever to threaten U.S. interests. It would have to simultaneously balance restoring its nuclear program, rebuilding Hezbollah, restocking its missile force, and managing its overall economic problems, all while still under sanctions. Simply put, Iran would have to make real choices as to its strategic direction. It would have lost all of its major deterrence systems and methods, and it could no longer turn to nuclear weapons as a cheap, quick option to restore them.
Should attempts to strike a deal fail, the United States must be willing to use its military.
A weakened Iran would yield dividends for the Middle East. The Iranian government might receive a limited boost in its popular support after U.S. attacks, but depending on their severity, targeting scope, and any unintended collateral damage, average Iranians might also see in them an opportunity to pressure the regime to change. Israel’s attack on Iran in October 2024 does not appear to have generated a notable “rally around the flag” effect, suggesting that a U.S. attack might not either. Furthermore, Tehran would have less time and fewer resources to harass or undermine its neighbors following a U.S. attack, and more incentive to work instead toward constructive regional security arrangements. Its setbacks would also reduce the pressure on other countries to acquire their own nuclear arsenals.
Finally, attacking Iran’s nuclear program could help shore up U.S. credibility—even though failure risks weakening it. Over the last two decades, the world has developed doubts about Washington’s commitment to addressing threats. The fault is bipartisan. The Obama administration drew a redline at former Syrian President Bashar al-Assad’s using chemical weapons and then refused to enforce it. Trump did not respond to Iran’s many attacks on U.S. forces and the energy infrastructure of U.S. allies, despite his pledges to act. If the U.S. government now sees Iran go nuclear despite repeated promises not to let it do so, challenger states will ask even more questions about the durability of U.S. commitments, exposing Washington’s friends and allies to grave risk. Striking Iran is certainly not the only (or perhaps even the best) way to enhance perceptions of American power. But it could play a part.
This assumes, of course, that Washington’s strikes would go far enough to ultimately succeed in preventing Iranian nuclear weaponization. The United States could, without a doubt, destroy Iran’s known nuclear facilities, but that alone would not prevent Iranian nuclear weapons acquisition. Such a feat would likely require more than one round of strikes, a long-term U.S. military presence, and U.S. readiness to expand its attack profile beyond nuclear facilities to target Iran’s decision-makers. As such, the United States would likely need to launch strikes that focus on regime assets or security forces, even if they prompt internal instability, and it should think now about how to design those strikes to reduce the negative consequences of that instability. Loose talk about so-called simple strikes—or how Washington can solve a decades-long challenge through a few bombing sorties—may sound appealing. But there is no substitute for a serious, honest, and sustained evaluation of what kinds of attacks would work, how long they would have to be sustained, how much they would cost, and how to avoid the worst outcomes.
A QUIET CRISIS
Washington’s power over Tehran’s nuclear calculus is ultimately limited. No one in the United States knows how Iranian officials are really looking at their current predicament. The return of maximum pressure sanctions could be the trigger for weaponization. But the blows Iran has already received from Israel, combined with its struggling economy, could already be enough to trigger it to go nuclear at a time of its own choosing. U.S. policymakers should begin to build into their own calculations that Iranian nuclear weapons are an eventuality to be managed, but there is a limited opportunity to avoid this outcome.
It is thus time for Washington to consider extreme steps. When the United States negotiated the JCPOA, it judged that keeping Iran to a one-year breakout time—the time required to produce enough usable nuclear material for a nuclear weapon—was needed to give the United States and its partners opportunities to find diplomatic off-ramps and, if necessary, to rally the world behind a military response. But that buffer is long gone; Iran has been breaking out since it started producing 60 percent enriched uranium, in 2021. The relative quiet of the present nuclear crisis between Iran and the United States speaks more to the raging nature of wars elsewhere than to restraint on Tehran’s part or effective diplomacy on Washington’s. There is no guarantee that the crisis will remain quiescent for much longer. The fact that military force may be necessary to prevent an Iranian nuclear breakout should be seen as a bipartisan policy failure. The downsides of a strike are grave, and so the safer course is to make another attempt at negotiation. But if that fails, Washington must be ready.