WASHINGTON — Senator Elizabeth Warren said Sunday night that she plans to support the Iran nuclear deal, offering her most explicit comments yet on the controversial issue gripping Congress.
Warren has previously offered supportive comments about the deal but had not said definitively that she would support an agreement that would force Iran to curb its nuclear program in exchange for the lifting of crippling economic sanctions.
“The question now before Congress — the only question before Congress — is whether the recently announced nuclear agreement represents our best available option for preventing Iran from acquiring a nuclear weapon,” Warren said in a statement to the Globe. After a number of briefings and consultations, she said, “I am convinced that it does.”
Warren is the latest high-profile Democrat to offer support for the deal. On Tuesday, Representative Sander M. Levin of Michigan, the longest-serving Jewish member of Congress, announced that he would support the agreement.
Warren’s decision could bolster the efforts of President Obama, who is aggressively lobbying Democrats to ensure that one of his biggest foreign policy accomplishments doesn’t go down in defeat.
Obama has been intensifying his push, both in private meetings with lawmakers, and in public. He is planning to deliver a speech on the Iran deal on Wednesday at American University. Secretary of State John Kerry, meanwhile, departed over the weekend for the Middle East to try to convince and reassure allies in the region.
Representative Seth Moulton, a Salem Democrat and a former Marine who served four tours in Iraq, announced Saturday that he would support the deal.
Representative Stephen F. Lynch of South Boston plans to support it, while Representative Michael Capuano of Somerville is “leaning strongly in favor,” according to a spokeswoman. But most other members of the Massachusetts delegation have not yet taken a position on the newly negotiated accord, saying they are still studying various aspects of it.
The deal has sparked bipartisan opposition, and critics are already airing national television ads and hoping to use the congressional recess to further pressure undecided lawmakers.
Congress has until mid-September to review the deal and pass a resolution of disapproval before it begins to take effect. It appears likely that such a resolution would have enough votes to pass, but given a veto threat from Obama, opponents will need to amass at least a two-thirds majority for an override.
Obama would need 34 members of the Senate or 146 members of the House in order to preserve the deal. If Republicans all band together in opposition, he could only afford a small number of Democratic defections.
Opponents of the deal say it contains a weak inspections process that could allow Iran to cheat and hide nuclear material to build a bomb.
They also say that the lifting of arms embargoes, which could start occurring within five years, would allow Iran to build and ship larger conventional weapons using a new influx of cash.
In her statement Sunday night, Warren said she believes the inspection regime is stringent enough to prevent Iran from pursuing a nuclear weapon.
“It allows us continuous access to key facilities and imposes stringent verification measures to ensure that Iran’s entire fuel cycle is peaceful,” she said. If Iran cheats, “we will be able to respond with the strength and support of the world behind us.”
Warren — whose first trip abroad as a senator was to Israel, which adamantly opposes the Iran deal — also emphasized that she does not view this as a game-changing approach to Iran.
“I do not trust the Iranian regime, which continues to terrorize its neighbors and to undermine international peace and stability, and this deal does not end our significant disputes with Iran,” she said. “We must continue to work with the international community to counter Iran’s dangerous behavior. But it is far easier to counter the ambitions of an Iran that has no nuclear weapon than it is to counter an Iran that can threaten the world with a nuclear bomb.”
Shortly after the deal was announced last month, Warren offered positive comments. She said two weeks ago, for example, that, “A negotiated solution is our best chance to hold Iran to no nuclear weapons.”
But she said it was only after briefings with Obama, Kerry, and Energy Secretary Ernest Moniz that she came to a final conclusion.
Warren said that she saw no reason not to try a diplomatic solution first — and resort to other alternatives if it fails.
“This nuclear agreement takes no options off the table,” she said. “If it ultimately fails, future actions to prevent a nuclear-armed Iran will only be enhanced by the knowledge we gain from closely monitoring the Iranian nuclear program throughout the length of the deal. If it ultimately succeeds, we will have neutralized a grave threat without resorting to war.”
“Those who oppose this deal have not disputed these facts and have presented no realistic alternatives,” she added. “Because I believe that this deal is our best available option, I support it.”
Matt Viser can be reached at email@example.com. Follow him on Twitter @mviser.