Though he had at one time had opposed it, President Barack Obama yesterday signed legislation to give the US Congress the power to review and potentially reject a nuclear deal with Iran.
Achieving a deal with Iran forms a central element of Obama's foreign policy, and the new law imposed conditions on his ability to act on his own.
The measure was signed yesterday, without ceremony at the White House.
Negotiators from the US, China, France, Russia, Great Britain and Germany had been seeking a deal with Tehran by the end of June.
Israel and some Persian Gulf nations had concerns Iran was only delaying its nuclear ambitions to get economic sanctions lifted.
Under the legislation Obama, would be barred from waiving congressional sanctions for at least 30 days even as lawmakers examined any final deal.
Congress would need to pass a resolution of disapproval to reject an agreement, an action Obama would veto. Obama had earlier threatened to veto legislation that placed conditions that Iran would never accept.
Speaking to a Jewish congregation in Washington yesterday, Obama said, "I will not accept a bad deal."
"This deal will have my name on it, so nobody has a bigger personal stake in making sure that it delivers on its promise."
The US and five other world powers had put together a delicate framework with Iran to keep it from developing nuclear weapons.
"Look, 20 years from now, I'm still going to be around, God willing. If Iran has a nuclear weapon, it's my name on this," the president said in an interview with The Atlantic, published on Thursday. "I think it's fair to say that in addition to our profound national-security interests, I have a personal interest in locking this down."
The president's signing of the legislation into law comes a week following Obama's meeting with leaders of Gulf nations at Camp David.
"Here at Camp David, we agreed that a comprehensive, verifiable solution that fully addresses the region's and international concerns about Iran's nuclear problem is in the security interests of the international community, including our (Gulf nation) partners," Obama said during a press conference last week.