The Iran nuclear issue presents a fundamental challenge to the progressive foreign policy agenda of presidential candidate Bernie Sanders. The insistence of Sanders to reenter President Barack Obama’s Iran nuclear deal will require him to sacrifice key elements of his foreign policy program or risk making the volatile Middle East much worse.

In the weeks and months prior to the signing of the Iran deal in June of 2015, longtime U.S. allies Saudi Arabia and other Gulf countries openly declared their intent to match the nuclear enrichment capabilities permitted to Iran under the proposed deal. A potential U.S. agreement on Iran’s nuclear program unnerved some U.S. allies, especially Saudi Arabia, and threatened the proliferation of nuclear capabilities across the Middle East. For Saudi Arabia, Obama’s deal represented a rapprochement between the United States and Iran and thus the betrayal by a longtime ally.