Now a done deal, the Iran nuclear agreement gained critical backing from three more Democratic senators Thursday, boosting White House hopes of blocking a disapproval resolution in the Senate so the president wouldn’t have to veto it.

Democratic Sens. Cory Booker of New Jersey, Mark Warner of Virginia and Heidi Heitkamp of North Dakota announced their support in quick succession for the deal that aims to curb Iran’s nuclear program in exchange for wide relief from economic sanctions.

The announcement from Booker, in particular, was closely watched because he was under immense pressure from segments of the Jewish community in New Jersey to oppose the deal, and New Jersey’s other Democratic senator, Bob Menendez, is an outspoken opponent.

In a statement, Booker voiced deep reservations but concluded: “It is better to support a deeply flawed deal, for the alternative is worse. Thus, I will vote in support of the deal. But the United States must recognize that to make this deal work, we must be more vigilant than ever in fighting Iranian aggression.”

Warner and Heitkamp added their voices not long after. Warner called the accord negotiated by the United States, Iran, Britain, France, Germany, Russia and China “the best option for advancing the goal of keeping Iran from obtaining a nuclear weapon.” Heitkamp declared: “If we reject this deal, Iran will be closer to developing a nuclear weapon, and we will reduce our standing and authority in the world.”

Their announcements came a day after Senate Democrats clinched the 34 votes needed to uphold President Barack Obama’s veto, if necessary, of a resolution of disapproval that Republicans are trying to pass this month. Booker, Warner and Heitkamp made it 37 Democratic or independent senators in favor of the deal, just four short of the 41 needed to allow senators to block a final vote on the disapproval resolution in the Senate and save Obama from exercising his veto power.

For their part, opponents have been reduced to trying to prevent a filibuster of the agreement. Powerless to stop the deal, they still hope to see congressional passage of a resolution putting Congress on record against it — even with the certainty that the measure would be vetoed.

“Since it looked like the administration was closing in on enough votes to sustain a presidential veto we’ve been asking people, just in fairness, ‘Let this come to a vote,'” said former Democratic-turned-independent Sen. Joe Lieberman, who’s rallying opposition to the deal. Given the importance of the agreement, “to have it defeated on a procedural tactic I think is unfair and unwise,” Lieberman said.

The American Israel Public Affairs Committee, which has spent millions opposing the deal, is also encouraging senators to allow a final vote on the disapproval resolution even if they intend to vote “no.”

“On an issue of this significance to the national security of the United States, the American people deserve a direct up or down vote on the agreement,” said the group’s spokesman, Marshall Wittmann.

The White House is eager to spare Obama the embarrassment of having to veto a disapproval resolution, and administration officials kept up their strong defense of the deal. In Florida Thursday, Vice President Joe Biden offered a robust endorsement of the accord, amid speculation about his own presidential ambitions

“I tell you, I firmly believe, and I will go into some detail here, it will make us and Israel safer, not weaker,” Biden said at a round-table discussion alongside Rep. Debbie Wasserman Schultz, D-Fla., chair of the Democratic National Committee, who remains uncommitted on the pact.

Biden sought to allay concerns of South Florida Jewish leaders who fear Iran won too many concessions. His motorcade passed by hundreds of protesters outside a Jewish community center where he spoke.

The Israeli government and GOP lawmakers who control the House and Senate contend the deal would keep Iran perilously close to developing nuclear weapons while enriching a government that has funded anti-U.S. and anti-Israel militants throughout the Middle East.

The deal sets Iran back so that it is at least a year away from being able to produce enough nuclear material for a weapon, before the restrictions ease after a decade.

All signs point to raucous wrangling when Congress comes back into session next week after a five-week summer recess.

Both the House and the Senate will plunge immediately into debate on the Iran measure as the week begins. On Wednesday, Donald Trump will join fellow GOP presidential candidate Sen. Ted Cruz at a rally outside the Capitol against the deal — even as Democratic presidential candidate Hillary Rodham Clinton defends it in a speech across town at the Brookings Institution.

House Republican leaders moved up debate on the disapproval resolution, ensuring that the House will go on record against the deal shortly after Congress returns from recess, regardless of the outcome in the Senate. The tally of House Democrats publicly favoring the deal ticked up toward 100 Thursday, but unlike their Senate counterparts, House Democrats don’t possess the tools as the minority party to block the resolution from passing.

(AP)