Moral obligation has been defined as a duty which one owes and which he ought to perform, but which he is not legally bound to fulfill. In order better to understand this doctrine as applied specifically to the Washington cases and law, let us consider the history and a brief statement of the principle.
Robert L. Palmer,
Moral Obligation as Consideration for a Promise in Washington,
10 Wash. L. Rev.
Available at: https://digitalcommons.law.uw.edu/wlr/vol10/iss4/2