Former US Secretary of State John Kerry says President Donald Trump “rushed into” the war on Iran “with a whole bunch of false assumptions”.

Kerry, who served as the top US diplomat under former President Barack Obama and helped negotiate the 2015 Iran nuclear agreement, made the remarks in an interview with CNN on Thursday.

Kerry questioned why Trump had not pursued negotiations with Tehran aimed at improving the nuclear deal, from which he unilaterally withdrew in 2018.

“If President Trump really wanted to change and make a better agreement, why didn’t he put something on the table?" he queried. “Why didn’t he actually make a proposal and have the Iranians respond to it or gain into another negotiation?

“No, he rushed into a war, particularly in the last months, with a whole bunch of false assumptions that have made life more expensive and more dangerous for people all over the world."

The former US secretary of state also said Trump had “put himself in a very disadvantaged position from which to try to negotiate,” but still believes it is possible for Washington to “get back to very close to the agreement we had.”

He further questioned whether military action could eliminate Iran's defense capabilities, saying, “You can’t bomb the memory of how to make a bomb.”

He urged the Trump administration to pursue “real diplomacy” on “several tracks at the same time: one more public and one very private, coordinated clearly.”

Asked about reports that Trump is considering another illegal act of aggression against Iran, Kerry said a new war would be an “enormous mistake”.

“That is not what will impress the Iranians or bring them to the table in a more serious way. In fact, it will push them away,” he added.

Former US president Obama warns war on Iran has left US ‘more vulnerable’ as Tehran holds Hormuz ‘veto power’

Barack Obama says the war on Iran has left the US ‘more vulnerable’ as Tehran continues to keep the Strait of Hormuz closed.

The US and the Israeli regime waged their first criminal war against Iran, which lasted 12 days, in June 2025. Their second aggression began on February 28, 2026, and came to a halt in early April after 40 days.

In both wars, Iran’s resistance and successful retaliatory operations forced the aggressors to accept a ceasefire.

Iran has also maintained a tight grip on the Strait of Hormuz since the early days of the second imposed war, sending energy prices soaring worldwide.

US Senator slams Trump’s ‘insane’ plan for new war

On Wednesday, US Senator Chris Murphy said he had been briefed on the US's plan to restart the war on Iran, denouncing it as "insane".

"You've heard a preview that it would be a short-duration plan. I'll just say this: their plan is insane," he said, speaking at an event organized by the Middle East Institute (MEI) in Washington.

"It will lead to devastating escalation and the likely destruction of our commitment to the rule of law."

Without disclosing specific details from the briefing, the senator warned that the plan, which could target civilian infrastructure in Iran, will lead to “a prolongment and an escalation of this war that would be devastating for our security interests.”