The Obama administration has secured enough support from United States lawmakers to prevent the landmark Iran nuclear deal from being scuttled in Congress.
The US Congress, which is set to reconvene next week, is expected to vote on the deal later this month. Under the accord, Iran agreed to curtail its nuclear programme in exchange for relief from crippling economic sanctions.
Most US lawmakers are opposed to the agreement, but Senate Democrat Barbara Mikulski - the 34th senator to back it - announced her support on Wednesday.
She said that while no deal is perfect, she believes it is the "best option available to block Iran from having a nuclear bomb".
She added that the alternatives - more sanctions or military actions - would not work.
"Maintaining or stepping up sanctions will only work if the sanction coalition holds together. It is unclear if the European Union, Russia, China, India and others would continue sanctions if Congress rejects this deal," she said. "Military action should be the last resort, since it will have only temporary effects versus the longer-term effects of this deal."
Also speaking on Wednesday, just minutes after Senator Mikulski's announcement, Secretary of State John Kerry reiterated his stance on the agreement.
"Without the deal, Iran would have several pathways to a bomb; with it, it won't have any," he said.
Responding to detractors, Mr Kerry, who spoke at the National Constitution Centre in Philadelphia, emphasised that the nuclear deal is not based on trust. "There is not a single sentence that depends on promises and trust," he said.
Instead, it is based on "verification and proof", he argued.
In his hour-long speech, he did not mention his administration's coup in obtaining the 34 votes needed to sustain a presidential veto, indicating that there is yet more work to be done.
Having 34 backers means that "when the President vetoes the resolution, there are not enough senators to override the veto", said Professor Bruce Jentleson from the Sanford School of Public Policy at Duke University.
The Obama administration's next goal is to see if it can gather at least 41 votes to prevent the Bill from getting to the Senate floor.
Obtaining 41 backers would mean that Republicans would not have enough votes - 60 are needed - to force a vote on the resolution of disapproval in the first place.
It would also save President Barack Obama from the drama and embarrassment of vetoing a Bill passed by Congress - a sure sign of a fractured Congress and lack of commitment for the accord.
"I wouldn't be surprised if one or two Republicans said it is in our national interest to move this issue on as we have other business to do in the Senate," said Prof Jentleson.
This would help make up the 41 votes that Democrats need.
But Associate Professor Daniel Franklin, who teaches political science at Georgia State University, said a "much more fruitful approach to opposing the Iran agreement would be to allow it to go into force so that, then, members of the Senate would have standing to sue".
He explained that the Senate could argue that the agreement is actually a treaty that is required to go through the ratification process - requiring a two-thirds majority of the Senate to vote for it.
But not all believe that the United States Senate would drag out the issue that way. "An effort to do that now would be seen as moving the goal posts. I don't think that would prevail... Many would object to it on the grounds of poor legislative procedure," said Prof Jentleson.