SDCL § 55-1-47: Extrinsic evidence not admissible to establish settlor's intent concerning no contest clause.

A no contest clause shall be construed to carry out the settlor's intent. Except to the extent the no contest clause in the trust is vague or ambiguous, extrinsic evidence is not admissible to establish the settlor's intent concerning the no contest clause. The provisions of this section do not prohibit such evidence from being admitted for any other purpose authorized by law.