This master thesis explores in depth the succession of two complaints lodged within the International Labour Organization (ILO) in 1961. The first complaint was lodged by Ghana against Portugal. The second was lodged by Portugal against Liberia. In each case, the complainant accused the opposing government of violating its commitment and international obligations against forced labor. This situation is unprecedented, since no member state of the organization has ever lodged a complaint against a government for unsatisfactory performance of international obligations. This dissertation shows that these two diplomatic "incidents" illustrate the growing internationalization of the issue of forced labor at the ILO, and the global delegitimization of the Portuguese colonial solution in international organizations. At the same time, the parallel study of the two complaints highlights the argumentation and rhetoric strategies used by colonial agents and Portuguese diplomats to confront their detractors, notably Ghanaians, with the aim of defending and normalizing colonialism, which was strongly criticized at the ILO during the sixties.