Apparently it's not so simple as he makes out.
Seems to me that this, like his Executive Order yesterday, is simply his carers and enabling letting him sign stuff and announce things to keep him happy.
He has a super stable genius idea, yells at one of the minions to make it so, and they give him a cobbled together thing to sign or announce that is functionally meaningless but means he can bask in the warm glow of self-satisfaction for a little while, before it wears off and he has to find his next ego boost.
What does international and domestic law say about withdrawing from the WHO and fulfilling financial obligations?
www.justsecurity.org