In a letter tweeted out on May 18, President Donald Trump mentioned his suspension of U.S. contributions to the World Health Organization (WHO). The letter also stated that

if the World Health Organization does not commit to major substantive improvements within the next 30 days, I will make my temporary freeze of United States funding to the World Health Organization permanent and reconsider our membership in the organization.

As a matter of policy, this is beyond foolish. As a matter of law, it raises several significant issues. Others have focused on whether Trump has the legal authority to suspend contributions. I want to focus here on Trump’s ability to withdraw the United States from the WHO – and on how this ability would be inhibited by a funding freeze.

The answer takes us back to the late 1940s. In 1948, the House and the Senate passed a joint resolution authorizing U.S. membership in the recently formed WHO. Because the WHO Constitution lacked a withdrawal provision, the joint resolution passed by Congress included a specific provision regarding exit:

In adopting this joint resolution, the Congress does so with the understanding that, in the absence of any provision in the World Health Organization Constitution for withdrawal from the Organization, the United States reserves its right to withdraw from the Organization on a one-year notice: Provided, however, That the financial obligations of the United States to the Organization shall be met in full for the Organization’s current fiscal year. (62 Stat. 441, 442 (1948).)

This provision originated in the Senate. The chair of the Senate Foreign Relations Committee, Arthur Vandenberg, proposed it in a hearing:

I submit to the committee the idea that we reserve to ourselves the right to withdraw on ninety days’ notice whenever we consider that the national interest requires, with the understanding, expressed in the same reservation that withdrawal, the act of withdrawal, includes an obligation to pay our assessments for whatever current year in which we withdraw, so that we do not abruptly upset their financial arrangements. (Hearing of July 1, 1947.)

While Vandenberg had proposed a 90-day notice period, later negotiations with the House led to the notice period being lengthened to one year.

The U.S. incorporated the joint resolution into its instrument of acceptance to the WHO Constitution. President Truman noted specifically in his statement of acceptance that he was “acting pursuant to the authority granted by the joint resolution … and subject to the provisions of that joint resolution.” (62 Stat. 2792 (1948).)

A few weeks after the U.S. deposited its instrument of acceptance, on July 2, 1948, the World Health Assembly unanimously adopted a resolution that “recognized the validity of the ratification by the United States of America.”

At the time the U.S. joined the WHO, customary international law was unsettled with respect to the conditions under which a nation could withdraw from a treaty that did not contain a withdrawal clause. Through its understanding – and the acceptance of this understanding by the state parties of the WHO – the U.S. ensured to itself a right of withdrawal as a matter of international law. This right appears conditioned, however, on both the giving of one year of notice and the full satisfaction of financial dues for the current fiscal year. While much of the U.S. funding for the WHO comes as voluntary contributions, the U.S. owes close to $60 million for the current year (and still has a balance outstanding from prior years).

As a matter of U.S. domestic law, it is an open question whether the president can unilaterally withdraw the U.S. from the WHO or whether congressional approval is needed for withdrawal. Because the U.S. joined the WHO via a joint resolution rather than through the mechanism set out in the Constitution’s Treaty Clause, it is what is sometimes termed an ex post congressional-executive agreement. Presidents have withdrawn the U.S. from such agreements on a few prior occasions. President Ronald Reagan withdrew the U.S. from UNESCO; President George W. Bush rejoined the United States to UNESCO (without intervening action by Congress); and Trump then re-withdrew the U.S. from UNESCO. But there is no judicial precedent on whether such unilateral withdrawal is indeed permissible, and the president’s power to do so is contested.

Congress’ joint resolution with respect to the WHO did not specify whether congressional approval would be needed for withdrawal as a matter of domestic law. But it did make clear that withdrawal should be “on a one-year notice” and that U.S. financial contributions “shall” be fully satisfied prior to withdrawal. To withdraw in any other manner would therefore be “incompatible with the … will of Congress.”

Thus, at a minimum, Trump must choose between freezing U.S. assessed contributions and following through on his threat of withdrawal. He cannot do both.

Image: The logo of the World Health Organization (WHO) at the entrance of their headquarters in Geneva, amid the COVID-19 outbreak. Photo by Fabrice COFFRINI/AFP via Getty Images