Sacred values are different from secular values in that they are often associated with violations of the cost-benefit logic of rational choice models. Previous work on sacred values has been largely limited to religious or territorial conflicts deeply embedded in historical contexts. In this work we find that the Iranian nuclear program, a relatively recent development, is treated as sacred by some Iranians, leading to a greater disapproval of deals which involve monetary incentives to end the program. Our results suggest (...) that depending on the prevalence of such values, incentive-focused negotiations may backfire. (shrink)