» Stephen Michael Kellat:
“Legal authority for him to do so is 22 USC 290c. I’m not saying he is right or wrong. NPR had a rushed article out earlier swearing he lacked any legal authority.
We only withdrew from UNESCO twice in its history. There is unfortunate precedent for doing this to a U.N. system agency. We were about to inflict it on the Universal Postal Union too but that got stopped at the last minute.”
It gives authority, so long as 1 year notice is provided and this year's obligations are paid in full. There, the president appears to be in violation of the very same rule that provides the authority to withdraw.
And the FAS wasn't saying he lacked authority; simply, that they disagreed with the decision. They urged him to rethink the decision, one which he likely put not actual thought into in the first place given the madness of pulling out of a global health organization in the middle of a global pandemic.