伊斯兰堡会谈注定失败——霍尔木兹海峡封锁给任何伊朗-美国协议又增添了障碍

Twenty-one hours of direct negotiations. The highest-level face-to-face engagement between Washington and Tehran since the 1979 Islamic Revolution.

And yet, U.S. Vice President JD Vance boarded Air Force Two in Islamabad on the morning of April 12, 2026, with no deal to end the U.S. and Israeli war against Iran, including an understanding over Tehran’s nuclear ambitions.

The U.S. has since begun what it says is a blockade of any and all ships originating in Iranian ports and would interdict every vessel that has paid a toll to Iran.

The collapse of the talks wasn’t the fault of bad faith or clumsy diplomacy. Rather, the talks failed because of structural obstacles that no amount of negotiating skill can overcome in a single weekend.

I and other exponents of international relations theory predicted this outcome. Understanding why matters enormously for what comes next.

The commitment barrier

The meeting in Islamabad wasn’t the first time representatives from the United States and Iran have sat around a table. In 2015, the Joint Comprehensive Plan of Action agreed to by Iran, the U.S. and five other nations showed that a formal agreement with nuclear inspections and verification is possible.

But that deal, which saw sanctions on Iran relaxed in return for limits over Tehran’s nuclear program, collapsed because the first Trump administration unilaterally walked away from the deal in 2018. In fact, the International Atomic Energy Agency had consistently certified Tehran was holding up its end of the bargain.

Then came the June 2025 strikes by Israel and the U.S. on Iran’s nuclear facilities.

Successive rounds of indirect talks between the U.S. and Iran followed in early 2026. But despite an Omani mediator telling the world that a breakthrough was within reach, the U.S. bombed Iran on Feb. 28, 2026.

Mohammad Bagher Ghalibaf, Iran’s parliamentary speaker who led Iran’s delegation in Islamabad, cited recent U.S. military action as a barrier to successful negotiations: “Due to the experiences of the previous two wars, we have no trust in the other side.”

Rather than an Iranian negotiating position, however, that was merely a description of a structural reality. Iran cannot be confident that any agreement it signs will be honored by this or subsequent American or Israeli administrations. And Washington isn’t sure Iran will not quietly rebuild what was destroyed once pressure lifts.

Moreover, while verification mechanisms on Iran’s nuclear program solve a technical problem, they do not solve the ongoing political one, in which both states are effectively still at war. Trust, once comprehensively destroyed, cannot be rebuilt in a hotel in Islamabad over 21 hours.

The scope of the problem

“The simple fact is that we need to see an affirmative commitment that (Iran) will not seek a nuclear weapon, and they will not seek the tools that would enable them to quickly achieve a nuclear weapon,” Vance said amid the Islamabad talks.

Iran’s enrichment knowledge is one of those tools. But the knowledge of how to enrich uranium to weapons-grade purity does not disappear when centrifuges are destroyed.

In this way, nuclear expertise is not like territory, equipment or sanctions relief. Centrifuges can be dismantled, and sanctions can be lifted in stages – both lend themselves to phased, verifiable agreements.

What the U.S. is demanding – a verifiable, permanent end to Iran’s breakout potential – requires Iran to surrender something that cannot be given back once conceded. Tehran and Washington both know this.

The problem is compounded by the extraordinary breadth of American demands on nonnuclear issues. Tehran’s demands included the release of frozen assets, guarantees around its nuclear program, the right to charge ships passing through the Strait of Hormuz, an end to Israeli attacks on Hezbollah and war reparations.

Washington’s 15-point proposal reportedly demanded a 20-year moratorium on enrichment, ballistic missile suspension, reopening of Hormuz, recognition of Israel’s right to exist and an end to Iran’s support for its regional proxy network, including Hezbollah, the Houthis and Hamas.

These are not two sides haggling over price. They are two sides who cannot even agree on what the negotiation is about.

Israel veto

Iran has also made ending Israeli strikes on Hezbollah in Lebanon a condition of any comprehensive settlement, conditions which Washington and Jerusalem have both rejected.

The result is a structural deadlock that has nothing to do with Iranian or American negotiating skill. Moreover, even if the two parties in Islamabad found common ground on the nuclear question, Israel could always torpedo any deal through a continuation of its military action in Lebanon and Iran.

And Israeli Prime Minister Benjamin Netanyahu did not need to be in Islamabad to shape what happened there. While Vance and Ghalibaf were negotiating, Netanyahu was on television, telling the world: “Israel under my leadership will continue to fight Iran’s terror regime and its proxies.” He made no mention of the talks at all – and has since come out strongly in support of the U.S. blockade.

What happens next?

Where does this leave the 14-day ceasefire, and what happens after that?

While the Trump administration immediately ramped up pressure on Tehran after the failure of talks, such escalation has thus far failed to bring about Iran’s capitulation in the current conflict.

Iran has declared the blockade an act of “piracy” and placed the country on “maximum combat alert,” with the country’s Revolutionary Guard warning that any military vessels approaching Hormuz would receive a “firm response.”

But like the nuclear negotiations, the blockade runs into the same wall. Iran controls the strait through mines, drones and geography. The U.S. can interdict ships but cannot reopen the strait without Iran’s cooperation – absent an unlikely military occupation.

As such, the blockade is largely a pressure tactic without a clear path for how it would resolve, which is exactly the problem that produced the Islamabad failure in the first place. The blockade also holds the risk of pulling in more countries. Trump’s interdiction order – “it’s going to be all or none” – in theory means the U.S. Navy would be prepared to interdict a Chinese tanker that has done business with Iran, risking a direct maritime confrontation with a nuclear power.

The alternative would be to let Chinese tankers through to avoid confrontation, but in so doing expose the blockade as a hollow strategy.

In either case, Beijing has become an active stakeholder in Iran’s leverage.

Same old problems … and a new one to boot

The structural obstacles that broke the Islamabad meetings will not dissolve before April 22, when the current ceasefire is due to expire.

The difficulty of convincing either side that any agreement will actually be honored will not be resolved by more talks, but is rather a product of what happened before the current negotiations. The nature of the nuclear question itself will not be negotiated away – it is a feature of physics and knowledge, not of political will. Moreover, Israel’s veto over any regional settlement will not disappear because Washington wants a deal.

Signs suggest that talks are still alive, and both Iran and the U.S. have shown a willingness to change previous red lines on the nuclear question even since the failure in Islamabad. Absent a larger shift in the status quo, however, the next round will face the same structural obstacles as before. But this time, there will be the added complication of a naval blockade that narrows, rather than expands, the diplomatic space.

Farah N. Jan does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.