Humans and human institutions can’t easily make credible commitments.
That seems right. (Perhaps with the exception of legal contracts, unless one of the parties is powerful enough to make the contract difficult to enforce.) And even when individual people in an institution have powerful commitment mechanisms, this is not the same as the institution being able to credible commit. For example, suppose you have a head of a state that threatens suicidal war unless X happens, and they are stubborn enough to follow up on it. Then if X happens, you might get a coup instead, thus avoiding the war.
That seems right. (Perhaps with the exception of legal contracts, unless one of the parties is powerful enough to make the contract difficult to enforce.) And even when individual people in an institution have powerful commitment mechanisms, this is not the same as the institution being able to credible commit. For example, suppose you have a head of a state that threatens suicidal war unless X happens, and they are stubborn enough to follow up on it. Then if X happens, you might get a coup instead, thus avoiding the war.