Compensation or Contagion? Public Support for International Cooperation after American Hegemony

Donald Trump’s United States (US) is abandoning its role as the hegemon of the liberal international order, accelerating its decline. While international relations theorists argue that coalitions of smaller states can compensate for the absence of a hegemon, research on states’ withdrawal from international institutions emphasizes the risk of contagion effects. In particular, increased international engagement requires public support. Are citizens in other democracies willing to compensate for the US’ withdrawal from international institutions such as the World Health Organization and the cuts to US development aid? Or do they follow Trump’s cues and advocate for nationalistic policies? We theorize two competing public opinion effects: First, recognizing that cooperation is in their national self-interest, citizens might increase their support for multilateralism. Second, “learning” from the US, citizens might reduce their support. To understand under what conditions citizens support compensation rather than contagion, we conduct a series of novel survey experiments among the citizens of four wealthy liberal democracies and key US allies: Canada, France, Germany, and Japan (n = 8000, fieldwork: December 2025). In the first experiment, we consider hypothetical cases of IO withdrawal, varying the IO’s policy area (climate, defense, economy, health), the loss of US contributions, and the presence of a joint response by other countries. In the second experiment, we zoom into the real-world case of the US’ withdrawal from the World Health Organization. The third experiment investigates support for foreign aid spending after the defunding of USAID by varying two pro-aid frames, a humanitarian frame focusing on the public health costs of aid cuts, and a security frame focusing on geopolitical costs of aid cuts. In times of politicization, our findings provide crucial insights into the resilience of public support for the liberal international order.