Under public international law a state can only exit a treaty according to (a) the treaty’s own terms or (b) the general rules in the Vienna Convention on the Law of Treaties (VCLT). The WHO Constitution itself contains no unilateral “withdrawal” clause, so termination or withdrawal normally requires either (1) following any specific WHO rules/conditions, (2) the consent of the other parties (i.e., the Health Assembly) under VCLT Article 54, or (3) one of the limited grounds for termination in the VCLT (e.g., material breach, impossibility, fundamental change of circumstances). U.S. domestic law (a 1948 joint resolution implementing U.S. accession) reserved a U.S. right to withdraw on one year’s notice and to be responsible for outstanding financial obligations; that domestic condition was accepted when the U.S. joined WHO, but under international law other states’ consent or applicable treaty rules still matter because the WHO Constitution lacks an explicit unilateral withdrawal mechanism.
E.O. 14155 (signed Jan 20, 2025) is a presidential order directing U.S. withdrawal from the WHO and directing executive-branch agencies to pause WHO funding, recall U.S. personnel, and pursue bilateral alternatives. An Executive Order cannot override international-law obligations or binding treaty procedures; it directs domestic executive action and agency implementation subject to existing U.S. law and appropriations. The Order cites the White House’s authority as President but must be implemented consistent with U.S. statute and international legal constraints (and is subject to judicial review).
Timing depends on the legal route. If the U.S. relies on the 1948 domestic condition (one-year notice) the effective date would be one year after notice (the White House and HHS fact sheets and press releases expected Jan 22, 2026). If the WHO/other members dispute the validity of unilateral exit (because the WHO Constitution lacks a withdrawal clause), the effective date may be contested and a transition may continue while the parties negotiate or seek dispute resolution. In practice the U.S. statement says it ceased funding and staffing immediately and will limit engagement to effectuate withdrawal, but WHO and legal commentators say any unilateral “immediate” departure is legally contested.
There is no public, authoritative U.S. list in the statement; the administration asserts all U.S. funding and staffing for WHO initiatives has ceased. In practice that would include assessed WHO contributions (regular and assessed program dues), U.S. voluntary grants and contracts to WHO programs, and U.S. staff seconded to WHO. Exact affected grants/positions must be identified in agency records (State, HHS, CDC, USAID) and budget notices; HHS/State fact sheets say U.S. participation in WHO committees, bodies and technical working groups has been paused and personnel recalled.
If the U.S. is not a WHO member, coordination can continue but will be more cumbersome: options include bilateral public‑health partnerships (direct CDC/state-to-state agreements), working with other multilateral bodies (e.g., Gavi, CEPI, UN agencies), contracting with WHO technical programs as a non‑member partner, and cooperating with scientific networks and national public‑health institutes. However experts warn loss of membership reduces access to WHO’s global surveillance networks, formal rule‑making (IHR), and convening power—making surveillance, vaccine allocation and rapid outbreak response harder and legally and operationally fragmented.
WHO has said the WHO Constitution contains no unilateral withdrawal clause and that the U.S. exit is therefore disputed; WHO officials (including the legal officer) have noted member consent and the Health Assembly’s role. WHO has also stated the U.S. has outstanding financial obligations; those unpaid assessments and any contractual or staff‑status claims form the basis for its position that the U.S. still owes money. Likely dispute‑resolution steps: diplomatic negotiation (Health Assembly/Executive Board), referral to legal bodies (e.g., arbitral tribunal or ICJ if states consent), and proprietary/contract remedies for unpaid bills—while WHO could seek withholding of privileges (per its rules) and the U.S. could pursue bilateral arrangements. In short, WHO’s legal position rests on its Constitution and the absence of an explicit unilateral withdrawal mechanism; resolving the disagreement will be diplomatic and legal and could take months to years.