The 2015 deal, which was spearheaded by the Obama administration over two years of negotiations, was long a target of the new US president, Donald Trump. But he decided to withdraw completely on Tuesday, reimposing all nuclear sanctions on Iran lifted under terms of the deal, effective immediately.
"Today's announcement weakens our security, breaks America's word, isolates us from our European allies, puts Israel at greater risk, empowers Iran's hardliners, and reduces our global leverage to address Tehran's misbehavior, while damaging the ability of future administrations to make international agreements," Kerry said.
"No rhetoric is required. The facts speak for themselves. Instead of building on unprecedented nonproliferation verification measures, this decision risks throwing them away and dragging the world back to the brink we faced a few years ago."
Trump has personally targeted Kerry on Twitter in recent days, after reports surfaced in his hometown newspaper, the Boston Globe, detailing the former secretary's private efforts to help salvage the deal upon a US withdrawal. Those efforts reportedly included conversations between Kerry and senior Iranian officials, including Iran's foreign minister, Javad Zarif, with whom Kerry built a strong personal relationship over the course of the nuclear negotiations.
"John Kerry can’t get over the fact that he had his chance and blew it!" Trump tweeted just hours before announcing the US withdrawal in remarks from the White House. "Stay away from negotiations John, you are hurting your country!"
In his response, Kerry said that European powers still had the ability to salvage the agreement.
"The extent of the damage will depend on what Europe can do to hold the nuclear agreement together, and it will depend on Iran’s reaction," he said.
"America should never have to outsource those stakes to any other country. This is not in America's interests. We should all hope the world can preserve the nuclear agreement."
And Obama issued one of the longest statements yet to come out of his office since Trump assumed the presidency, warning of a new war in the Middle East as a result of his successor's actions.
"I believe that the decision to put the JCPOA at risk without any Iranian violation of the deal is a serious mistake," Obama said, referring to the formal name of the agreement, the Joint Comprehensive Plan of Action. "Without the JCPOA, the United States could eventually be left with a losing choice between a nuclear-armed Iran or another war in the Middle East."
"We all know the dangers of Iran obtaining a nuclear weapon. It could embolden an already dangerous regime; threaten our friends with destruction; pose unacceptable dangers to America’s own security; and trigger an arms race in the world’s most dangerous region," Obama continued.
"If the constraints on Iran’s nuclear program under the JCPOA are lost, we could be hastening the day when we are faced with the choice between living with that threat, or going to war to prevent it."