The Fragile U.S.-Iran Ceasefire: Issues to Watch

After over a month of fighting, the United States and Iran agreed to a two-week ceasefire. The ceasefire is fragile, and many of the key factors that will determine its durability are unclear. Below are six issues to watch as negotiations play out.

Ceasefire or a Settlement?

For now, the United States, Israel, and Iran have agreed to a ceasefire and only a ceasefire. Numerous contentious issues remain unresolved, ranging from Iran’s nuclear and missile programs to Tehran’s support for proxies and repression of protesters at home. Tehran, for its part, seeks an end to U.S. sanctions, the right to enrich uranium, an end to Israel’s attacks on Lebanon, and other demands, as well as guarantees that attacks on Iran will not resume. The war itself has also generated new demands: Iran seeks compensation for the devastation caused by U.S. and Israeli bombing and is claiming that it will demand payment for tankers seeking to transit the Strait of Hormuz. The two sides are far apart, and both seek to convince audiences at home that they have won—something that will further complicate negotiations.

It is possible that the ceasefire itself will be the settlement: The United States, Israel, and Iran will not come to a final deal, but the ceasefire will continue indefinitely, with the risk of a flare-up hovering over the region.

Iran’s Nuclear Program

Iran’s nuclear program has been at the center of the U.S.-Iran conflict for decades, and over the years the United States has tried sanctions, cyberattacks, negotiations, and limited military force to stop it. The United States and Israel destroyed much of Iran’s program in the 12-day war in 2025, and the 2026 war saw further attacks. Much of Iran’s facilities and stockpiles are currently buried beneath tons of rubble.

Throughout this period, Iran has claimed it does not seek a nuclear weapon but has ferociously defended its right to enrich uranium—an approach that the United States and Israel have long believed is a not-so-secret path to a nuclear weapon.

The nuclear issue remains unresolved, and Iran even claims (probably falsely) that the United States has accepted its right to enrichment as part of the ceasefire deal. Although the U.S. and Israeli campaign means that Iran is further from a bomb, it might redouble efforts to acquire one, believing that only a nuclear weapon can protect it given the United States’ and Israel’s conventional military superiority.

The Lebanon War

The ceasefire covers attacks on Iran, but Israel claims it does not cover its operations against Hezbollah in Lebanon—and Israel has continued attacks there. The Lebanon war has been almost as devastating as the Iran war, with almost 1,500 Lebanese killed and over 1 million Lebanese displaced, and Israel is establishing a buffer zone on the Lebanese side of the Israel-Lebanon border.

Weakening Iran will probably weaken Hezbollah, but the path is messy and risky. Sustained Israeli military pressure may degrade Hezbollah’s capabilities and constrain its ties to Tehran, yet it simultaneously weakens Lebanon’s institutions faster than they can recover and risks leaving a power vacuum rather than a stronger state. Hezbollah is likely to be battered but still present, the state further hollowed out, and the country more vulnerable to prolonged internal and regional shocks.

Terror and Revenge

U.S. and Israeli strikes on Iran have heightened the near-term risk of international terrorism by Tehran and its partners, including Lebanese Hezbollah. As Iran has already sought to widen the conflict by targeting U.S. partners in the Gulf, terrorism offers another avenue to impose costs on Washington and its allies. If hostilities resume, Iranian leaders may judge that escalating pain is necessary to deter further attacks. Even in a ceasefire environment, the incentive for retaliation remains strong: Tehran has a history of plotting attacks to avenge senior figures, and the recent losses—over 250 high-ranking officials—are unprecedented in scale. At the same time, the broader conflict is catalyzing anti-Israel and antisemitic violence that is not directly orchestrated by the Iranian state.

Yet Iranian terrorist efforts may falter or prove counterproductive. The United States and Israel have long invested heavily in countering Iranian networks, and their demonstrated intelligence penetration in the latest war suggests they may be well positioned to disrupt plots abroad. A successful attack on U.S. soil could also generate the domestic support for military action that has thus far been limited. Similarly, attacks against allied countries risk hardening public opinion and political will against Iran, strengthening rather than weakening the coalition aligned with Washington and Jerusalem.

It is also plausible that the terrorist threat may diminish. Iran and several of its key proxies, including Hamas and Hezbollah, have absorbed significant military and organizational damage. In the aftermath, they may be more cautious about provoking additional retaliation through high-profile terrorist operations, particularly if doing so risks further degrading already weakened capabilities.

How Do Allies and Partners View the United States?

Perhaps the greatest long-term damage to the United States from the Iran war will be in its relationships with allies around the world. The war is deeply unpopular in Europe and has increased inflation and hurt growth in Asia and the rest of the world as well. Adding insult to injury, the United States did not consult with NATO allies before the war and then U.S. officials berated them for not taking on difficult missions like opening the Strait of Hormuz after things began to get ugly. More practically, the United States used up scarce air defense and other military assets in the Iran war, leaving stockpiles diminished for opposing Russia and helping allies deter China. China sees the war as an opportunity to increase its influence and portray the United States as erratic and bellicose.

It is possible that the world will move on quickly and that Beijing’s aggressive posture toward Taiwan and the South China Sea will set back any Chinese gains in negatively portraying the United States. Nevertheless, the United States is likely to find its allies more hesitant and more instrumental in their dealings with the United States.

War After the War

Even after major fighting subsides, Israel and Iran are likely to remain locked in a persistent, lower-level conflict rather than transition to stable peace. Militarily, Israel has not achieved decisive victory, and it may see continued attacks as necessary to stop Iran from rebuilding missile stockpiles and to put pressure on Iranian leaders. Tehran may believe it will be targeted regardless of restraint, reinforcing a logic of continued resistance and retaliation.

Domestic and strategic pressures on both sides further reinforce this dynamic. For Iran’s leadership, ongoing confrontation can help justify repression and deflect attention from economic hardship and political unrest. For Israel, the long-standing “campaign between the wars” approach favors continued strikes to keep Iran and its proxies weak and off balance rather than allowing them to rebuild. The result is a likely pattern of recurring clashes—cyberattacks, proxy violence, limited strikes, and periodic escalation—rather than a clean postwar settlement. Even if the United States seeks to step back, its close alignment with Israel means it will remain exposed to Iranian retaliation, making a cycle of “wars after the war” difficult to escape.

In the end, the ceasefire is less a resolution than a pause in a conflict whose underlying drivers remain not only intact but, in some cases, intensified. The nuclear issue is unresolved, Lebanon is destabilized, the risk of terrorism persists, and U.S. alliances have been strained—all while Israel and Iran retain strong incentives to continue a shadow war that periodically erupts into open violence. Even if large-scale fighting does not immediately resume, the United States faces a region marked by persistent instability, emboldened adversaries, wary allies, and a continuing cycle of escalation that will be difficult to control or conclude.

Daniel Byman is the director of the Warfare, Irregular Threats, and Terrorism Program at the Center for Strategic and International Studies in Washington, D.C. He is also a professor at Georgetown University.