A central question facing the White House is whether to trade U.S. actions for Iranian ones as a way of bringing both nations back within the fold of the 2015 agreement, something European nations generally support but many in Congress would be likely to oppose.

Secretary of State Antony Blinken and other newly installed officials held their first strategy session on the Middle East on Friday, and Blinken joined a group discussion with the European nations that were parties to the 2015 deal: Britain, France and Germany. Russia and China were also signatories to the deal.

“This is not a decisional meeting. It’s not a meeting where the policy will be concluded, and it’s not a meeting the president of the United States will be attending,” White House press secretary Jen Psaki said of the gathering of senior officials at the White House.

The timeline for a potential resurrection of the deal is “really up to Iran,” she added. “If Iran comes back into full compliance with the obligations” of the deal, “the United States would do the same, and then use that as a platform to build a longer and stronger agreement that also addresses other areas of concern.”

Iran is one of Biden’s most vexing foreign policy challenges, as he seeks to engage its leaders while challenging its influence in the Middle East and its support of terrorism. Even U.S. officials who back the Iran deal as a crucial step in curbing its nuclear ambitions view the nation as a severely destabilizing force.

The Biden administration has not directly addressed a suggestion by Iranian Foreign Minister Mohammad Javad Zarif that the United States move toward rejoining the deal at the same time that Iran takes steps to come back into compliance.

One fundamental question discussed in the U.S. meetings Friday, with a decision still to come, is whether to seek incremental moves to get the process moving again or to insist on one big agreement that goes beyond Iran’s nuclear program.

The administration has said — and many in Congress have insisted — that any deal that releases Iran from sanctions must include negotiated restrictions on its ballistic missile program and on its support for proxy forces fighting in other countries such as Iraq, Syria and Yemen.