Legal experts and critics have denounced the withdrawal as a violation of US law, which requires that Washington settle more than $260 million in outstanding fees before cutting ties with the United Nations health agency. Under that statute, a notice period of one year and full payment of dues are prerequisites to any lawful exit from the WHO. However, the US has not paid its accumulated dues for 2024 and 2025 and has ceased future transfers of funds, raising questions about compliance with domestic legislative requirements.

Public health specialists warn that the departure could undermine both US and global health security. The WHO has been central to coordinating responses to pandemics, tracking infectious diseases, and sharing vital health information across borders. Losing American participation, including funding, expertise, and influence, could weaken international systems for early detection and response to emerging health threats and leave the US isolated from critical global surveillance networks.

International appeals for a rethink have failed, and the WHO now faces a severe budget crisis after losing its largest single funder. The organisation has been forced to downsize staff and slash programmes, raising concerns among global health officials about its capacity to protect populations amid ongoing and future health challenges.