I recall from elementary game theory that the ability to provably bind oneself to an action (ie make a promise you can’t back out of) is extremely valuable in negotiation. It is hugely important in our day to day lives (loans, service contracts etc), but also politics.

The US ability to have people believe their promises has been shredded by Trump (Eg Iran Nuclear Treaty). We just renegotiated NAFTA to the USMCA, and now all of a sudden it’s no good? How can we trust that this deal will last more than 15 minutes? How can we have any sort of partnership with an organization like this?