Speaking to CNBC-TV18, Dixon said the nuclear issue remains the central challenge for the proposed deal, which is expected to be formally signed in Geneva on Friday, June 19.
“If Iran is not going to agree to stop enriching uranium and address its existing stockpile, then that is where this agreement will fall apart,” Dixon said. “That’s ultimately the red line for Trump.”
His comments come after US President Donald Trump announced that Washington and Tehran had reached an agreement to end hostilities. Trump said he had authorised the “toll-free opening of the Strait of Hormuz” and the removal of the US naval blockade of Iranian ports, raising hopes of stability in global energy markets.
Crude oil prices fell below $80 a barrel following the announcement, as traders welcomed the prospect of uninterrupted oil flows through one of the world’s most important shipping routes.
However, major questions remain unanswered. Iranian state media has reported that uranium and nuclear facilities will remain in Iran under the agreement, while discussions on a final settlement are expected to continue over a 60-day period after the initial signing.
Dixon said the Trump administration’s primary objective has always been preventing Iran from obtaining a nuclear weapon.
“That has been the one point repeatedly emphasised by the Trump administration: no deal is possible until there is movement on Iran’s commitment not to acquire a nuclear weapon,” he said.
He added that any agreement would need to be viewed favourably in Washington and compared with the 2015 nuclear deal negotiated under former US President Barack Obama.
“If this agreement doesn’t end up looking better than the JCPOA, then politically it will look bad for Trump in the US,” Dixon said.
The ceasefire itself remains delicate. Israel has publicly distanced itself from parts of the agreement. National Security Minister Itamar Ben-Gvir criticised the deal, saying Israel is not a party to it and that it does not guarantee Israeli security. Defence Minister Israel Katz has also stated that Israeli forces will not withdraw from territory seized in Lebanon.
Despite those concerns, Dixon said the agreement appears more credible than previous attempts to end the conflict.
“It seems that, in this case, there is much more agreement behind it, or at least it feels real,” he said. “From what we’re hearing, it seems we’re at a position where peace will hold.”
Hasaan Hashmi Pirzada, a geopolitical expert, described the arrangement as a “very fragile but historic step towards de-escalation” and said Pakistan had played a central role in bringing both sides together.
According to Pirzada, Pakistan acted as the primary diplomatic bridge between Washington and Tehran, facilitating back-channel communications and helping shape the framework that led to the ceasefire.
“Pakistan has played an indispensable and central role as the primary diplomatic bridge between Washington and Tehran,” Pirzada told CNBC-TV18.
While many details remain undisclosed, Pirzada said the framework appears to include an immediate ceasefire across all fronts, including Lebanon, the reopening of the Strait of Hormuz to commercial shipping and partial access for Iran to frozen assets to support reconstruction efforts.
Reports in Iranian media have suggested that a $300 billion reconstruction or compensation fund could be created for Iran, though no official confirmation has been provided. There have also been claims that Iran may seek to impose a service fee on vessels using the Strait of Hormuz.
Dixon questioned whether such a fee could be enforced over the long term.
“The real question is whether it is enforceable. I’m sceptical that it is,” he said.
The agreement has been welcomed by several world leaders, while European governments have reiterated that Iran must never acquire a nuclear weapon. The deal is expected to be signed in Switzerland on Friday, with mediators hoping it will pave the way for broader negotiations aimed at securing a lasting peace in the region.
