5G networks are at the center of geopolitical competition. The United States has denounced market leader Huawei's ability to break into allies' sensitive networks and it has tried to convince Europeans to ban the Chinese group from their 5G markets. How are European governments and industries reacting to 5G politicization? This article argues that government-industry interactions in the handling of politically salient issues are mediated by the country's political system. In executive-dominated countries, the government would centralize policymaking. In parliament-dominated countries, the government would delegate politically salient issues to the industry to bypass diffuse powersharing and fragmented coalition-building. The article adds that political economy acts as an intervening variable. In public governance ecosystems, governments and industries interact through informal coordination; in private governance ecosystems, the two actors rely on formal contracting. The empirical analysis focuses on British, Dutch, French, and Italian reactions to 5G politicization, yielding favorable results to the hypotheses.