Former US national security advisor Jake Sullivan has claimed that Donald Trump’s peace deal with Iran is an “unalloyed win” for the Islamic Republic.

Speaking with UnHerd’s Freddie Sayers, Sullivan said the Memorandum of Understanding signed by Iran and the United States on Wednesday gave “significant advantages” to Iran and indicated that “the United States has basically lost this war.”

The agreement signed between Trump and Iran says the Islamic Republic will never have a nuclear weapon, and commits to the re-opening of the Strait of Hormuz and an end to the US blockade, as well as the creation of a $300 billion fund for Iranian reconstruction. However, Sullivan said that the US was now effectively paying “reparations” to Iran and has “ended up in a worse position today than we were before the war started”. He added: “Essentially what you’re looking at here is a deal to reopen the Strait of Hormuz with a massive financial windfall to Iran, and then a commitment to negotiate a set of nuclear issues that at present are completely unresolved.”

Sullivan served as the US national security advisor from 2021 to 2025 under former president Joe Biden, and previously helped negotiate the Obama administration’s 2015 Iran nuclear deal, which limited the Islamic regime’s stock of nuclear material and relieved US sanctions on the country. Trump derided the agreement as the “worst deal in history”, and withdrew the US in 2018 during his first presidential term.

In the UnHerd interview, Sullivan argued that the Obama deal had put Iran’s nuclear programme in a “box”, and that Trump’s withdrawal allowed Iran to “move forward again”. Yet with the MOU, he said, Trump has been forced to recognise “the same reality we had to acknowledge a decade ago”, namely that Iran will not accept a complete end to its nuclear enrichment programme. The MOU’s reference to Iran’s “nuclear needs”, Sullivan stated, was a pullback from Trump’s previous declaration that the country could not have a civilian nuclear programme.

“We have to recognise that the US actually could have gotten all of the statements Iran made on its nuclear programme in this deal before it went to war,” he said. “And [the US] wouldn’t have had to pay to reopen the Strait of Hormuz because the Strait wouldn’t be closed.”

While Sullivan celebrated the end of the war, he cautioned that Israel may be a “spoiler” to negotiations due to widespread opposition to the deal. Further, pointing to Trump’s deal to end the war in Gaza, where second-phase peace plans have stalled, he argued that the Iran peace deal may be left “open-ended”.

“Maybe they reach some interim deals about specific things like down blending the stockpile, but I don’t think you’re going to see a comprehensive nuclear deal,” Sullivan said. “I think that will just drag indefinitely.”

Watch the full interview here.