The Iran nuclear deal worked for Obama and it can work for Biden — but only if Congress doesn't stand in the way

• After a year and a half of talks, the US and Iran are close to reviving the 2015 nuclear deal.
• If Washington and Tehran succeed, the future of the deal will be squarely in the hands of Congress.

After a year and a half of talks, the United States and Iran are edging closer to reviving a deal that would block Tehran's path to producing a nuclear weapon and provide much needed sanctions relief for the Iranian people.

If Washington and Tehran succeed, the future of the deal will be squarely in the hands of Congress. This long-sought diplomatic achievement would improve US national security and the security of the Persian Gulf region, and avoid a much worse likely alternative — military action that could lead to another bloody and costly war in the Middle East. So now, Congress needs to get on board.

If it happens, the Biden administration should be applauded for this diplomatic breakthrough. President Biden was clear from the beginning of his administration that he supported a US reentry into the deal, but only on the right terms. Earlier this year, when the deal seemed close at hand, Iran demanded certain steps (such as the removal of Trump administration's sanctions on Iran's Revolutionary Guard), which the Biden administration decided were a bridge too far.

Biden held firm and waited for Iran to shift its position, which it apparently did. Recent news, however, underscores that the prospects for success remain uncertain.

But even if we get a deal, it cannot be implemented until it goes through Congress, which has 30 days to review it. There are three strong reasons for Congress to support the Iran deal:

The deal worked before and can work again. The deal was working well until former President Donald Trump, for domestic political reasons, recklessly abandoned it in 2018. Tehran was complying with the deal until the US withdrew, practically inviting Iran to advance its nuclear program. When the deal was in place, Iran was 12 months away from having enough nuclear material for a bomb, and now, without the deal, Iran is only weeks away (making that material into a warhead for a missile would take longer).

The deal on the table will absolutely reverse much of Iran's progress. While it won't get us back to the original breakout timeline, it will give us six months and reinstate much-needed insight into Iran's nuclear activities which is more than enough time to respond should we find evidence of Iran cheating. But without the deal we could see Iran rush toward a bomb in no time.

The alternative is much worse. Biden said during his recent trip to the Middle East that he would use military force "as a last resort" to keep Iran from obtaining a nuclear weapon. But if a renewed Iran Deal fails, war becomes much more likely — and would be a disaster.

The US war in Iraq cost hundreds of thousands of lives, trillions of dollars, destabilized the entire region and is now widely considered to have been a historic blunder. For comparison, Iran's population is twice that of Iraq, with an active military almost three times larger. Iran also controls access to the Persian Gulf. Blocking the Strait of Hormuz could reduce global oil supply by an estimated 30%.

As former Secretary of Defense Robert Gates put it, "If you think the war in Iraq was hard, an attack on Iran would, in my opinion, be a catastrophe." Amidst the war in Ukraine, global inflation, and tensions with China, the last thing we need is another international crisis.

The Iran deal is popular with voters. Recent polling shows voters are worried about the prospect of a nuclear Iran and are more likely to support members of Congress who prioritize diplomacy over war.  Nearly half (45%) of likely voters say they would be "more likely" or "much more likely" to vote for a candidate who supported a renewed nuclear deal with Iran.

By comparison, only 15% say a candidate's support for the deal would make them "less likely" or "much less likely" to vote for them. And voters overwhelmingly favor diplomacy over military action across party lines: 83% of Democrats, 79% of Independents, and 72% of Republicans agree the US should focus on diplomacy to end Iran's nuclear program.

Second chances are rare, so let's not waste this one. It was a tragic error to abandon the Iran deal in 2018, as Tehran's nuclear progress shows. We know the deal worked before. Given the likely catastrophic consequences of another war in the Middle East, and strong public support for diplomacy, members of Congress have every reason to support a revived agreement.

The Iran nuclear deal is still good politics and good policy, and it deserves Congress' full support.

Emma Belcher is president of Ploughshares Fund, a global peace and security Foundation. Tom Z. Collina is director of policy at Ploughshares Fund.