How can vulnerable states adjacent to countries embroiled in civil war avoid conflict contagion? Jordan has all the classic attributes highlighted in the literature as creating vulnerabilities susceptible to spillover. It adjoins Syria and Iraq where jihadists have operated freely. It has a weak economy, refugees pouring in from adjacent conflicts and is home to hundreds—if not thousands—of jihadists. Moreover, jihadists consider the Jordanian regime to be traitors—who conspire with the enemies of Islam—and they want to replace it with an Islamic state. However, as we show, very few jihadist attacks have happened in Jordan. We test three hypotheses for the limited spillover. Our analysis suggests a state policy that we dub “calibrated repression” is the most significant explanation. This means that Jordan protects against spillover by repressing jihadist attempts at infiltrating the kingdom and clamping down on local terrorist cells linked to the Islamic State while keeping other domestic jihadist elements in check through co-optation. The regime restrains the use of force against less acute threats and displays some leniency towards radicals when the situation allows. Our findings speak to the broader literature on spillover and offer insights into the understudied topic of mechanisms limiting spillover in high-risk environments.