"Walking away from the JCPOA [Joint Comprehensive Plan of Action] turns our back on America’s closest allies, and an agreement that our country’s leading diplomats, scientists, and intelligence professionals negotiated," Obama wrote in his statement.
Taking aim at specific points from Trump's speech earlier in the day, Obama said. "debates in our country should be informed by facts, especially debates that have proven to be divisive."
Obama then set forward six separate points refuting Trump's claims that the agreement has done nothing to prevent Iran from obtaining a nuclear weapon, that it has a set expiration date, and that it should have addressed a wider array of Iran's destabilizing behavior in the Middle East.
"Because of these facts, I believe that the decision to put the JCPOA at risk without any Iranian violation of the deal is a serious mistake," Obama said. "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."
In a briefing with reporters, national security adviser John Bolton refuted critics who claimed President Trump's announcement was intended as a precursor for U.S. boots on the ground in Iran.
"They would be badly mistaken if that's what they thought," Bolton said.
The statement from Obama marks the fifth time he has spoken out in direct opposition to a policy being pursued by President Trump – including twice regarding Republicans' failed efforts to repeal and replace the Affordable Care Act, the withdrawal from the Paris Climate Agreement, and Trump's announcement ending the Deferred Action for Childhood Arrivals, or 'DACA' program.
The public criticism by a former president of his successor is indeed an unusual step, and one Obama's aides have said he is deliberately wary of in an attempt to avoid becoming a direct target of Trump and other Republicans.
However, Obama argued in his statement that Trump's Iran pullout should be seen as more than just a hit against his own legacy.
"In a democracy, there will always be changes in policies and priorities from one Administration to the next," Obama said. "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."