Power transitions among major states have shaped the course of cooperation in the history of the international system. We study this relationship from a public opinion angle by examining the effect of a potential power transition on attitudes towards bilateral trade liberalization. Power transitions can spur political and economic conflict because the rising power gains greater influence over the course of world politics, including trade rules, allowing it to assert its national interest and the interests of its citizens. This implies that citizens in the rising power are more supportive of bilateral economic cooperation than citizens in the declining power. Empirical findings from parallel, survey-embedded experiments in China and the United States lend support to this conjecture. Great Power competition, therefore, interferes with current international economic affairs – an aspect that has received less attention in previous research on trade politics.