Democratic senators pushed the Biden administration to commit to diplomacy with Iran — and warned of the consequences of failure — during a Wednesday confirmation hearing for two high-level State Department nominees.

Sens. Chris Murphy (D–Ct.) and Ed Markey (D–Mass.) asked whether it is still the Biden administration’s goal to return to the 2015 nuclear deal with Iran, while Tim Kaine (D–Va.) and Chris Van Hollen (D–Md.) claimed that an escalation with Iran could pose grave risks to U.S. forces in Iraq and Syria.

Ambassador Wendy Sherman, the Biden administration’s nominee for deputy secretary of state, confirmed that U.S. policy is still to return to the Joint Comprehensive Plan of Action before opening talks on other issues.

Under the 2015 JCPOA, six world powers had agreed to lift the international embargo on the Iranian economy in exchange for Iran agreeing to restrictions on its nuclear program.

Former President Donald Trump broke JCPOA in 2018 by imposing “super maximum economic pressure” and demanding a “better deal.” Iran later retaliated by escalating its own nuclear activities, although it continues to insist that it will return to compliance with the deal once economic sanctions are lifted.

Sherman, who had helped negotiate the original 2015 deal, raised eyebrows during Wednesday’s confirmation hearing with statements that suggested President Joe Biden had dropped his commitment to a “compliance-for-compliance” deal around the JCPOA.

“2021 is not 2015 when the deal was agreed, nor 2016 when implemented,” she stated in her opening remarks. “The facts on the ground have changed, the geopolitics of the region have changed, and the way forward must similarly change.”

Sherman told Sen. Mitt Romney (R–Utah) that Biden’s goal is “a deal that is longer and stronger.”

Murphy, a staunch supporter of diplomacy with Iran, called it a “fantasy” that Iran “would come to the table on everything all at once” and asked Sherman to clarify Biden’s policy.

“It makes me a little nervous when we hear terms like ‘longer and stronger.’ Again, I think many of us supported the [JCPOA] on its terms,” Murphy said. “By expanding out the number of things we want to talk about at this negotiating table, I worry that we may be setting ourselves up for failure.”

Markey pointed out that the JCPOA had reduced Iran’s “breakout time” — the amount of time it takes to stockpile enough highly-enriched uranium to build a weapon — from two months to more than a year.

Sherman confirmed that the Biden administration  “hopes to get Iran in full compliance with the deal. Then we would be in full compliance with the deal. Then we would build from that to get a longer and stronger agreement.”

The United States and Iran are both currently locked in a standoff as both sides insist that the other move first. On Sunday, Iran turned down an offer to meet with U.S. and European officials to discuss the JCPOA.

Meanwhile, U.S. forces and Iranian-backed militias have been clashing in the Middle East. On Thursday, U.S. forces bombed a militia position in Syria in retaliation for rocket attacks on U.S. bases in Iraq. The morning of the hearing, a U.S. contractor died of a heart attack after militants fired rockets at Al-Asad Air Base in western Iraq.

Kaine portrayed the diplomatic tension and military escalation as a vicious cycle.

“At the same time that [Thursday’s airstrike] happened, the U.S. had an offer on the table with Europeans for Iran to come to the table for a no-preconditions discussion,” he said. “The administration, from my conversations, was actually pretty optimistic that Iran was going to accept that offer. Then missile strikes happened on Thursday, and then Iran turned down the offer on Sunday.”

Kaine warned that the continuing tit-for-tat could lead to “a significant military engagement or war without a discussion in Congress…in front of the American people,” and called for repealing the 2002 war authorization against Iraq.

Van Hollen noted that U.S. policy is to prevent Iran from getting a nuclear weapon, and “resolving that through diplomatic means is better than going to war.”

“If we were to go to war with Iran, our troops in Iraq would be put in grave danger,” he said. “I think it’s pretty clear that they would be right in the line of fire, so I encourage you to continue your efforts with respect to JCPOA compliance-for-compliance, and I hope we can get to that point as quickly as possible.”

Not all Democrats agreed with a return to the JCPOA. Senate Foreign Relations Committee Chair Robert Menendez (D–N.J.) said that returning to the 2015 deal “would not be sufficient.”

“Without bipartisan support, no deal would be durable,” Menendez said.

But it was unclear whether Sen. James Risch (R–Idaho) — the highest-ranking Republican on the committee — would see any deal signed by Biden as legitimate.

“I think all of us had this experience where our European partners and others would come in and say, well, you know America, you breached your agreement that you entered into,” Risch said. “I kept telling them, you did not have an agreement with America! You had an agreement with Barack Obama and John Kerry.”