Part IV: Parties · Last amended 1969 · Last verified July 16, 2026
In one sentenceRule 15-6-24 lets a person intervene in a pending South Dakota action as of right, when a statute grants that right or the applicant’s unrepresented interest is at stake, or with the court’s permission when a shared legal or factual question justifies it, following a set filing procedure.
(a)Intervention of right. Upon timely application anyone shall be permitted to intervene in an action:
(1)When a statute of the state confers an unconditional right to intervene; or
(2)When the applicant claims an interest relating to the property or transaction which is the subject of the action and he is so situated that the disposition of the action may as a practical matter impair or impede his ability to protect that interest, unless the applicant’s interest is adequately represented by existing parties.
(b)Permissible intervention. Upon timely application anyone may be permitted to intervene in an action when an applicant’s claim or defense and the main action have a question of law or fact in common. When a party to an action relies for ground of claim or defense upon any statute or executive order administered by a federal or state governmental officer or agency or upon any regulation, order, requirement or agreement issued or made pursuant to the statute or executive order, the officer or agency upon timely application may be permitted to intervene in the action. In exercising its discretion the court shall consider whether the intervention will unduly delay or prejudice the adjudication of the rights of the original parties.
(c)Intervention procedure. A person desiring to intervene shall serve a motion to intervene upon the parties as provided in § 15-6-5. The motion shall state the grounds therefor and shall be accompanied by a pleading setting forth the claim or defense for which intervention is sought. The same procedure shall be followed when a statute gives a right to intervene. When the constitutionality of an act of the Legislature affecting the public interest is drawn in question in any action to which the state or an officer, agency or employee of the state is not a party, the party asserting the unconstitutionality of the act shall notify the attorney general thereof within such time as to afford him the opportunity to intervene.
Plain-English Summary
Rule 15-6-24 gives an outsider two distinct paths into a pending lawsuit. Intervention of right applies when a state statute confers an unconditional right to intervene, or when the applicant claims an interest in the property or transaction at issue and the case’s outcome could, as a practical matter, impair or impede the applicant’s ability to protect that interest — unless an existing party already represents it adequately.
Permissive intervention is discretionary. The court may let someone in when their claim or defense shares a question of law or fact with the main action, and it must weigh whether the intervention would unduly delay or prejudice the original parties’ rights. The rule gives a specific example of this discretionary route: when a party relies on a statute or executive order administered by a government officer or agency, that officer or agency may seek to intervene.
To get in, a person desiring to intervene serves a motion on the existing parties the same way papers are served under § 15-6-5. The motion must state its grounds and come with a pleading laying out the claim or defense the applicant wants to assert, and the same procedure applies when a statute grants the right to intervene. Rule 15-6-24 adds one more safeguard: when a case not involving the state challenges the constitutionality of a legislative act affecting the public interest, the party raising that challenge must notify the attorney general in time to give the state an opportunity to intervene.
Frequently Asked Questions
When can someone intervene in a South Dakota lawsuit as a matter of right?
Rule 15-6-24(a) allows intervention of right when a state statute confers an unconditional right to intervene, or when the applicant’s interest in the property or transaction at issue could be impaired by the case’s outcome and is not already adequately represented.
Can a court say no to intervention even when the applicant shares a legal question with the case?
Yes. Permissive intervention under Rule 15-6-24(b) is discretionary, and the court must consider whether allowing it would unduly delay or prejudice the rights of the original parties.
What has to be filed along with a motion to intervene?
Rule 15-6-24(c) requires the motion to state its grounds and be accompanied by a pleading setting out the claim or defense for which intervention is sought.
Can a government agency intervene in a case that relies on a regulation it administers?
Yes. Rule 15-6-24(b) lets a federal or state officer or agency seek permissive intervention when a party’s claim or defense relies on a statute, executive order, or regulation that officer or agency administers.
What happens if a case questions the constitutionality of a state law and the state is not already a party?
Rule 15-6-24(c) requires the party challenging the law’s constitutionality to notify the attorney general in time to give the state an opportunity to intervene.
Amendment History
(a)SDC 1939 & Supp 1960, § 33.0413; SD RCP, Rule 24 (a), as adopted by Sup. Ct. Order March 29, 1966, effective July 1, 1966; as amended by Sup. Ct. Order No. 2, March 31, 1969, effective July 1, 1969.
(b)SD RCP, Rule 24 (b), as adopted by Sup. Ct. Order March 29, 1966, effective July 1, 1966.
(c)SDC 1939 & Supp 1960, § 33.0413; SD RCP, Rule 24 (c), as adopted by Sup. Ct. Order March 29, 1966, effective July 1, 1966.
Source & verification. Rule text and History are
reproduced verbatim from the South Dakota Codified Laws, published by the
South Dakota Legislative Research Council. Last verified July 16, 2026.
· Official source
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