Jean-Paul Sartre, the existentialist philosopher, once described mauvais foi-or bad faith-as the act of deceiving oneself to escape the anxiety of confronting uncomfortable truths. In the complex realm of geopolitics, this concept extends beyond individuals to nations and leaders, who often find themselves at a crossroads between ethical responsibility and self-interest. This tension is particularly evident in the field of global health. As the world grapples with pandemics, health inequities, and the existential threat of climate change, Sartre’s principle of bad faith provides a powerful lens through which to examine the actions of global actors. The COVID-19 pandemic starkly revealed the tendency of powerful nations to act in bad faith. While publicly proclaiming their commitment to global solidarity and equitable vaccine distribution, many wealthy countries secured the lion’s share of vaccine supplies-often at the expense of lower-income nations. This behaviour highlighted the contrast between vaccine nationalism and vaccine diplomacy. Developed countries, driven by a desire to maintain power and influence, prioritized vaccinating their citizens and close allies, underscoring the strategic rather than altruistic nature of their actions. At the same time, vaccine diplomacy emerged as a tool for expanding geopolitical influence, with countries like China and Russia leveraging their vaccine developments to forge alliances and enhance their global standing. Despite widespread acknowledgement of the urgent need to address climate change, many governments continue to act in bad faith by prioritizing short-term economic gains over long-term environmental sustainability. In response to these disparities, the COVAX initiative was established to ensure fair access to COVID-19 vaccines for all countries, regardless of income level. However, despite COVAX’s efforts, high-income countries still secured the majority of vaccine doses. By November 2020, when the first COVID-19 vaccines were ready for rollout, nearly 7.25 billion doses had already been pre-purchased globally. According to the Duke Global Health Innovation Center, high-income countries secured the majority of these doses. India, however, ordered 1.5 billion doses-more than any other country-while the U.S. pre-purchased 1.01 billion doses for its 330 million citizens, a stark contrast to India’s 1.3 billion. This imbalance deepened the divide between the Global North and the Global South, leaving poorer nations to navigate the pandemic with limited resources and delayed access to vaccines. The influence of self-interest is not limited to pandemic responses. In the context of climate change, mauvais foi is once again prominently displayed. Despite widespread acknowledgement of the urgent need to address climate change, many governments continue to act in bad faith by prioritizing short-term economic gains over long-term environmental sustainability. This deception is glaringly evident in the ongoing reliance on fossil fuels. In 2023, China consumed 140 exajoules of fossil fuels, equivalent to approximately 5.8 billion tonnes of hard coal, solidifying its position as the world’s largest coal consumer. The United States followed with 76 exajoules, while India consumed 35 exajoules, surpassing the combined total of Europe and North America for the first time. Crude oil consumption also reached new heights in 2023, surpassing 100 million barrels per day for the first time, while global coal demand exceeded the previous year’s record. These statistics, drawn from the 2024 Statistical Review of World Energy by the Energy Institute, underscore the ongoing reliance on fossil fuels despite global pledges to reduce carbon emissions. The U.S.-China rivalry exacerbates this issue, creating a “prisoner’s dilemma” where mutual distrust and competition prevent substantial cooperation on climate initiatives. By downplaying the full impact of their actions, these countries deceive not only the global community but also themselves, as the long-term consequences of inaction will ultimately harm all nations. However, it is crucial to recognize that the pressures on these nations are immense, involving complex trade-offs between economic stability and environmental responsibility. While their actions may appear hypocritical, they are often driven by a need to balance these competing demands-a nuance that complicates the critique of bad faith. Moreover, while vaccine nationalism and climate inaction represent clear cases of mauvais foi, it is also important to consider the underlying factors that drive these behaviours. Economic pressures, political instability, and public opinion often compel leaders to prioritize immediate national interests over global responsibilities. These complexities suggest that bad faith is not merely a matter of moral failure but is also deeply intertwined with the structural challenges of global governance. Sartre’s concept of mauvais foi remains a relevant lens for analyzing the actions of nations and international organizations. By recognizing and reforming these behaviours, global actors can move beyond bad faith toward a truly equitable and sustainable global health system. Proposals such as a pandemic treaty based on “one nation, one vote” could democratize global health governance, ensuring more equitable decision-making. Reforming the WHO’s funding structure to reduce donor influence would enhance its independence and ability to act in the global health interest. Strengthening global health security requires building resilient healthcare systems, improving disease surveillance, and ensuring fair distribution of medical resources during crises. However, achieving these goals demands more than just structural reforms; it requires a shift in the mindset of global leaders. They must move beyond the self-deception of mauvais foi and embrace the interconnectedness of global health. Only by confronting the uncomfortable truths of their actions and recognizing the shared vulnerabilities of humanity can nations begin to work towards genuine global solidarity and a more just world. The writer is a medical practitioner.