Postwar functionalism focused the role of the World Health Organization (WHO) in advancing peaceful change on scientific and technical cooperation. By the 1970s, the influx of low- and middle-income countries (LMICs) as member states called for greater attention to health development needs and the ways postwar liberal internationalism was a structural determinant of ill-health. Contested perspectives about WHO’s mandate and core functions ensued. Major donor countries, concerned about the organization’s politicization, reasserted their influence by shifting the organization’s budget to donor-controlled voluntary contributions. Despite ongoing efforts to reform the WHO, new global health initiatives proliferated, weakening the organization’s standing as the directing and coordinating authority on international health work. The COVID-19 pandemic laid bare WHO’s limited authority and resources but also the critical importance of both scientific and political leadership in responding to shared global health threats. This has renewed debates about WHO’s role in advancing peaceful change amid a now complex and crowded global health governance landscape. While some argue for the organization to return to its scientific and technical focus, promoting interdependence and trust among member states requires meaningful political processes.