More than a dozen national organizations sent a letter to President Biden on Friday urging him to show “leadership and political courage” and save the Iran nuclear agreement, saying it’s “perplexing” that he is allowing domestic politics to stand in the way of renewing a sound non-proliferation agreement.

“As organizations committed to diplomatically preventing a nuclear-armed Iran, we are incredibly concerned about the nonproliferation implications of this development,” the letter states. “Now more than ever, leadership and political courage are needed to prevent the complete death of the agreement and evade its likely consequences — war with Iran or a nuclear-armed Iran.”

The groups — which include J Street, Indivisible, and the Quincy Institute for Responsible Statecraft — note that Biden himself, and many senior officials in his administration, have previously stated that Trump’s withdrawal from the deal was a “disaster.” Some of these officials have also pointed out, the letter adds, that opponents of the deal pushed Trump to create domestic political poison pills — like designating Iran’s Islamic Revolutionary Guard Corps a terror group — for the specific purpose of making it difficult for any successor to re-enter the deal.

“This is why it is all the more perplexing that your administration has allowed this ‘political move’ to stand in the way of a strategically vital renewal of the JCPOA,” they write. “As you and your former colleagues in the Obama administration correctly made clear: Iran is a dangerous actor — but it will be all the more dangerous if it possesses nuclear weapons.”

The groups say Biden will ultimately be responsible for the JCPOA’s failure, as it’s just another way of “doubling down on Trump’s maximum pressure strategy,” which they call “a self inflicted wound.”

“Allowing the perfect to be the enemy of the good will put our world in grave danger, with yet another dangerous state in possession of the most deadly weapons on earth,” said Nancy Parrish, Executive Director of Women’s Action for New Directions, another signatory of the letter. “President Biden, we implore you to double down on negotiations and bring the Iran deal to the finish line before it’s too late.”

Dylan Williams, J Street’s senior vice president for policy and strategy, noted that “a supermajority of Jewish American voters and the consensus of the Israeli security establishment support restoration of the agreement over the escalating nuclear crisis and regional insecurity brought on by Trump’s disastrous approach.”