Progressive and Catholic groups are urging President Joe Biden to break the diplomatic gridlock with Iran and move to rapidly rejoin the 2015 international nuclear deal.

On Wednesday, more than 30 progressive groups released a letter urging Biden to “follow through quickly” on rejoining the Joint Comprehensive Plan of Action, either by taking the first step or by agreeing to move simultaneously with Iran.

Meanwhile, late last month, 27 Catholic groups led by the Maryknoll Office for Global Concerns had published their own open letter asking the president to “offer sanction relief as an initial show of good faith to bring Iran back to the table.”

The two letters are a sign that the Biden administration is facing increasing pressure to extend an olive branch to Iran and break a diplomatic deadlock. Biden had promised to return to the JCPOA and begin broader U.S.-Iranian talks, but the two countries are stuck in a standoff as both sides insist that the other move first.

Republicans have been pressuring the Biden administration to take a harder line by refusing to lift the embargo on the Iranian economy until Iran agrees to broad concessions on its conventional missile arsenal and regional military policies.

Biden also fears the wrath of Senate Foreign Relations Committee Chairman Bob Menendez (D–N.J.) and other hawkish Democrats — who have previously aligned with Republicans on the Iranian issue — Politico reported on Monday.

The Wednesday letter by progressives represents an attempt to push back, arguing that hawks ”oppose the very idea of diplomacy let alone any deal with Iran, regardless of the details.”

It argues that the JCPOA was one of Biden’s “most important and unequivocal promises during the campaign, one shared with every other major Democratic primary candidate, and one that was an important sign that you were prepared to move U.S. foreign policy away from the reckless, belligerent unilateralism of Donald Trump.”

The letter’s signatories include the activist organization Demand Progress, the Bernie Sanders-aligned group Justice Democrats, the longtime progressive activist group MoveOn, the left-leaning veterans’ group VoteVets, and the foreign policy think tank Win Without War..

The Ploughshares Fund, a foundation focused on nuclear non-proliferation, left leaning pro-Israel group J Street, and the Friends Committee on National Legislation, a Quaker lobby group, also signed the letter. So did Responsible Statecraft’s parent organization, the Quincy Institute.

“We stand ready to help engage a U.S. public that overwhelmingly supports diplomacy,” the letter states. “The most important and effective support for your efforts will come from those who have worked in support of U.S.-Iran diplomacy for years, not from those who have opposed it and been so consistently and disastrously wrong about the key foreign policy questions of the 21st century.”

Under the original JCPOA, six world powers had agreed to lift the international embargo on the Iranian economy if Iran restricted its nuclear program and agreed to international inspections. Iran initially complied with the JCPOA, but former President Donald Trump broke the deal in 2018, imposing harsh economic sanctions on Iran while demanding a “better deal.”

Iran subsequently ramped up its own nuclear activities, in violation of the JCPOA, a year after Trump left the deal. Iranian officials insist that they will reverse these steps once the United States lifts its sanctions.

Biden has promised to ditch Trump’s policy and return to the JCPOA — but only after Iran returns to compliance.

“We support your policy of ‘compliance for compliance,’ but the fact of the matter is that the United States was the first to violate the deal,” the  letter by progressives to Biden states. “It is therefore reasonable to expect the United States to at the very least take concurrent steps with Iran to rejoin it.”

Catholic groups went even further, explicitly asking Biden to offer sanctions relief before Iran makes the first move. Lifting the embargo “would be a first step toward rebuilding the trust of Iran, our other partners in the JCPOA, our allies around the world, and countries such as North Korea where we seek to eliminate nuclear weapons,” their letter argues.

The letter also argues that “sanctions relief can come with clear conditions,” as Biden has the power to reimpose sanctions if Iran fails to “comply within a short, clear, realistic timeline.”

Both the progressive and Catholic letters argue that economic sanctions on Iran have been a cruel form of collective punishment.

The standoff has intensified in recent weeks. Iran restricted international inspectors’ access to its nuclear sites late last month. The United States and its allies then rolled out a proposal to censure Iran at the International Atomic Energy Agency.

Last week, Iran rejected an invitation for a meeting with the United States and other JCPOA parties. Iranian officials had wanted assurances that the meeting would focus on JCPOA re-entry, but were refused those assurances, the National Interest has reported.

Meanwhile, Iranian-backed militias and U.S. forces have clashed in Syria and Iraq, leaving a U.S. contractor and an Iraqi militiaman dead.

“The longer the elements of ‘maximum pressure’ remain in effect, the more it will continue to embolden hardliners and make U.S.-Iran diplomacy more difficult,” the letter by progressives states. “The recent escalation in military activity  between the United States and reported Iranian proxies in Syria and Iraq only shows how urgently needed a new course of action is.”