National boundaries during Nazi rule in Upper Silesia ironically became more fluid. Nazi Gleichschaltung (coordination) had co-opted or disbanded Catholic and workers’ associations, but Polish groups were uniquely protected by League of Nations minority rights. Locals flocked to Polish youth groups, sport leagues, lay associations, and theater troupes, using Polish protections to reestablish social and religious networks. To gain material benefits, some Polish nationalists joined the Nazi Party or even the SS. Nazi leaders, exasperated by this "in-between stratum," began targeting Polish nationalists after the Geneva Accord protections expired in 1937. Many Polish activists were arrested or expelled or sent to concentration camps in 1939. Yet Polish-language usage in private or informal settings continued. During World War II, a tacit bargain arose, as Berlin prioritized the need for coal, grain, and soldiers from Upper Silesia over widespread repression. Polish speakers largely ignored or even openly defied the demands of Nazi racial conformity, and Polish-language usage increased regionally thanks to an influx of Polish POWs and forced laborers.