As populist radical right parties muster increasing support in many democracies, an important question is how mainstream parties can recapture their voters. Focusing on Germany, we present original panel evidence that voters supporting the Alternative für Deutschland (AfD)—the country’s largest populist radical right party—resemble partisan loyalists with entrenched anti-establishment views, seemingly beyond recapture by mainstream parties. Yet this loyalty does not only reflect anti-establishment voting, but also gridlocked party-issue positioning. Despite descriptive evidence of strong party loyalty, experimental evidence reveals that many AfD voters change allegiances when mainstream parties accommodate their preferences. However, for most parties this repositioning is extremely costly. While mainstream parties can attract populist radical right voters via restrictive immigration policies, they alienate their own voters in doing so. Examining position shifts across issue dimensions, parties, and voter groups, our research demonstrates that, absent significant changes in issue preferences or salience, the status quo is an equilibrium.