Former U.S. Secretary of State Antony Blinken ’84 said the future of U.S. and Israeli involvement in the war with Iran will likely come down to “markets and munitions” as both sides exchanged ceasefire proposals and renewed attacks this week.

The prospect of steep declines in global energy markets, U.S. financial exchanges, and stockpiles of Israeli missile interceptors will serve as “guardrails” on how far the administration will go, Blinken told David Sanger ’82, a White House and national security correspondent for The New York Times during a talk Tuesday evening at Harvard Kennedy School.

Blinken spoke of the very different approaches the last three presidents have taken with Iran and reflected candidly on the nation’s handling of the war in Gaza during his time leading the State Department during the Biden administration.

“The problem now is this: I think the president could if he chose, and I suspect this is what will happen, just declare victory and game over,” he said about the administration’s next move in Iran. “Except it won’t be, because Iran will have actually demonstrated something that we suspected but didn’t actually know, which is it has ability to leverage the Strait of Hormuz in ways that are profoundly disruptive and give it an asymmetric advantage in the region and indeed around the world.”

The Obama administration considered taking military action against Iran to prevent it from developing a nuclear weapon. But U.S. leaders decided instead to pursue a diplomatic solution, which resulted in the 2015 Joint Comprehensive Plan of Action, said Blinken, who was deputy national security adviser in 2013 when an interim pact was reached and deputy secretary of state when the deal was finalized.

At the time, the U.S. concluded that military action could result in unacceptable risks and that ultimately, Iran could end up simply rebuilding its enriched uranium stockpile and stashing it deeper underground and out of reach, he said.

President Trump withdrew the U.S. from the agreement in 2018 during his first term. Iran still had some centrifuges and since then has continued to produce fissile materials and “moved from a breakout time of more than one year to a matter of a week, maybe two weeks,” he said, referring to how long it would take to enrich enough material to create a weapon.

Now, because of the U.S. and Israel bombing campaign that began Feb. 28, there’s a “strong chance” that if the Iranian regime survives — which seems likely, given its diffuse structure — that nation will be more determined than ever to build a nuclear weapon, Blinken said.

During the campus event, Blinken also responded to criticism over the Biden administration’s support for Israel even as its war with Hamas, triggered by the deadly terrorist attack of Oct. 7, 2023, resulted in a humanitarian crisis in Gaza.

Blinken said Gaza was a challenge he confronted daily while in office and something he still “continues to grapple with.”

“When it comes to Gaza … given the level of human suffering, given the horrific loss of life among Palestinian women, men, and children, you can’t help but ask yourself on a regular basis could we, should we, have done something different?” he said.

“And the short answer is, maybe yes.”

He noted the U.S. was faced with trying to balance several competing interests as well as the limits to its influence in the conflict.

Blinken conceded the Biden administration was not able to get a lasting ceasefire but said he did manage to help put a tentative halt in place, arrange for the release of some Israeli hostages and Palestinian prisoners, and get 25,000 aid trucks going into Gaza.

Making the case for diplomacy, Blinken said it’s more important than ever that the U.S. renew efforts to bring coalitions of countries and other stakeholders together to work through issues as the world faces rapid technological and social change, the ascendancy of China as a superpower, and the erosion of post-World War II rules-based order and institutions.

“That’s what I fear is one of the things we’re losing in the approach that we’re taking now,” he said. “There is so much strength to be found in numbers and in alignment, in convergence, in the approach to a given problem. I think that’s where we need to go, certainly to get back to, as we deal with China in the years ahead.”