Barack Obama on Tuesday condemned Donald Trump’s decision to violate the Iran nuclear deal as “misguided” joining a throng of other outspoken Democratic critics - even as many Republicans praised the move.
The former president, for whom the landmark 2015 accord was a signature foreign policy accomplishment, issued a lengthy written statement shortly after Trump announced the US would break with the Joint Comprehensive Plan of Action (JCPOA) despite the urging of European allies and some of his own advisers.
“In a democracy, there will always be changes in policies and priorities from one Administration to the next. But the consistent flouting of agreements that our country is a party to risks eroding America’s credibility, and puts us at odds with the world’s major powers,” Obama said.
Since leaving the White House, Obama has responded to only a handful of Trump’s policy decisions, including his travel ban on several Muslim-majority countries, decision to pull the US from the Paris climate accord, and move to rescind protections to young, undocumented immigrants.
In line with previous comments, Obama did not mention his successor by name. Much of the former president’s statement instead sought to clarify the facts surrounding the Iran deal and its terms, while insisting that the accord was working.
“I believe that the decision to put the JCPOA at risk without any Iranian violation of the deal is a serious mistake,” Obama said.
“The United States could eventually be left with a losing choice between a nuclear-armed Iran or another war in the Middle East.”
Obama’s concerns were echoed by John Kerry, the former secretary of state, who led US negotiations of the accord.
Kerry said Trump’s decision “breaks America’s word” and expressed hope the deal could continue without America.
“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,” Kerry said.
“America should never have to outsource those stakes to any other country,” he added. “This is not in America’s interests. We should all hope the world can preserve the nuclear agreement.”
Political reaction in Washington split along partisan lines, with Republicans rushing to defend the president and Democrats sounding the alarm over the prospect of war.
Top Democrats decried Trump’s announcement, including some who had lobbied against the deal.
Robert Menendez, the top Democrat on the Senate foreign relations committee, warned Trump was making “a grave mistake”.
“With this decision President Trump is risking U.S. national security, recklessly upending foundational partnerships with key U.S. allies in Europe and gambling with Israel’s security,” Menendez, a senator from New Jersey who was a staunch opponent of the accord, said in a statement.
“President Trump owns the consequences of today’s decision,” he added.
Tim Kaine, a Democrat on the Senate foreign relations and armed services committees, said Trump was “creating a new global nuclear crisis” by violating the deal.
“President Trump has set us on a dangerous road where war becomes more likely, especially as his advisers beat the drums for regime change, which should never be a goal of US policy,” said Kaine, who co-authored legislation in 2015 that enabled Congress to review the Iran deal before US sanctions could be lifted. 
Republicans were quick to support Trump’s decision, in another sign of the party’s reluctance to challenge the president. Although some Republicans had expressed reservations about pulling out of the accord, criticism was muted after the announcement.
“I have always believed the best course of action is to fix the deficiencies in the agreement,” House speaker Paul Ryan said in a statement. “It is unfortunate that we could not reach an understanding with our European partners on a way to do that.”
Ryan, who plans to retire at the end of the year, called the deal “deeply flawed” and praised Trump for sending “a strong statement that we can and must do better”.
Kevin McCarthy, the House majority leader, said Trump was staying true to what he promised as a candidate. “This is something the president campaigned on,” McCarthy told Fox News.
The Iran deal, which was struck in 2015 by six world powers and Iran after nearly two years of negotiations and designed to restrict Iran’s nuclear program in exchange for sanctions relief, has long been a target of Republicans.
The Trump administration has insisted it will pursue a new deal aimed at preventing Iran from developing a nuclear weapon. But Tehran has sounded a defiant tone and warned of “historic regret” if America were to leave the nuclear accord.