South Dakota Codified Laws
Chapter 06 - Consideration For Contracts
Section 53-6-2 - Legal or moral obligation as good consideration.

53-6-2. Legal or moral obligation as good consideration.
An existing legal obligation resting upon the promiser or a moral obligation originating in some benefit conferred upon the promiser or prejudice suffered by the promisee is also a good consideration for a promise to an extent corresponding with the extent of the obligation, but no further or otherwise.

Source: CivC 1877, §907; CL 1887, §3531; RCivC 1903, §1225; RC 1919, §840; SDC 1939, §10.0502.