“If we don’t sell them arms, someone else will,” has become a well-known refrain in the arms trade world, implying that partners cut off from U.S. defense exports will quickly source them from other suppliers. But there is reason to believe that there is far more complexity to the issue than suggested by this simple axiom. Multiple factors shape the cost-benefit analysis of partners considering turning to alternative defense exporters as a result of arms transfer suspensions, curtailments, or conditions imposed by the United States, suggesting a need to reexamine key assumptions underpinning the U.S. security cooperation enterprise.