Seventy-five of the world's top nuclear nonproliferation specialists issued a joint statement Tuesday endorsing the Iran nuclear deal, calling it "a strong, long-term, and verifiable agreement that will be a net-plus for international nuclear nonproliferation efforts."

The nonpartisan Arms Control Association, based in Washington, said the Joint Comprehensive Plan of Action (JCPOA) agreement between Iran and the P5+1 nations "meets key nonproliferation and security objectives" and that they "see no realistic prospect for a better nuclear agreement."

Signatories include former senior U.S. nonproliferation officials; former director of the IAEA Hans Blix; former CIA agent Valerie Plame and her husband; Thomas Pickering, a retired diplomat and former U.S. ambassador to Israel; Morton Halperin, a foreign policy veteran of three administrations; senior fellows from the Council on Foreign Relations and the Brookings Institution; and several former United Nations disarmament officials.

The nuclear accord would see Iran limit its nuclear ambitions in exchange for international sanction relief.

If the agreement is fulfilled by all parties - the U.S., U.K., France, China, Russia, Germany and Iran - it will advance "the security interests of the P5+1 nations ... reduce the risk of a destabilizing nuclear competition in a troubled region ... and head off a catastrophic military conflict over Iran's nuclear program," the group said.

The statement comes as the Obama administration is rushing to sell the deal to a skeptical American public and lawmakers ahead of a congressional vote next month, expected by Sept. 17, according to Politico.

Most polls taken since the agreement was announced July 14 have consistently found that more people oppose the deal than support it, according to The Washington Times.

Practically all congressional Republicans oppose the deal, as do many Israeli officials, who argue that the deal is rife with risky loopholes and concessions. One provision, they say, could allow Iran to stall inspections for up to 24 days before allowing the IAEA inspectors to examine suspicious activity.

The Arms Control Association, however, claims that monitoring and verification provisions found in the deal would "make it very likely that any future effort by Iran to pursue nuclear weapons, even a clandestine program, would be detected promptly, providing the opportunity to intervene decisively to prevent Iran from acquiring a nuclear weapon."

One concern of opponents not addressed by the statement is the sunsetting of the deal's main provisions after 15 years, after which, some say Iran could install advanced centrifuges and build a nuclear weapon in weeks.

Two key senators - Democratic Sen. Chuck Schumer and Republican Sen. Jeff Flake - recently announced their opposition, and the GOP-led House and Senate are expected to pass a resolution of disapproval, with leaders in both chambers criticizing the accord.

It's unclear whether opponents can achieve the two-thirds majority in both chambers to override a promised veto from President Obama. Senate Majority Leader Mitch McConnell of Kentucky grudgingly told The Associated Press on Monday that he thinks Republicans will struggle to get the override. If they do, Obama would be barred from lifting U.S. sanctions. Obama will need to get support from 34 Senate Democrats to sustain a veto, while 20 have announced their support thus far. In the House, Obama will need support from 146 Democrats, with 48 already voicing support.