The short answer is yes – South Dakota’s statutory law still classifies adultery as a criminal offense in 2026, though prosecutions are rare and penalties are modest. Section 32‑21‑1 of the South Dakota Codified Laws defines “adultery” and makes it a Class 1 misdemeanor, punishable by up to 30 days in jail and a fine of up to $1,500. While the law remains on the books, modern courts focus more on its relevance to divorce and child‑custody matters than on criminal enforcement.
Statutory Basis
South Dakota’s criminal code, codified at § 32‑21‑1, expressly criminalizes consensual sexual intercourse between a married person and someone who is not their spouse. The statute has been unchanged since its adoption in the early 20th century, reflecting the state’s historically conservative moral framework. Penalties are capped at a Class 1 misdemeanor, the lowest level of criminal offense, indicating legislative intent to keep the sanction symbolic rather than punitive.
Enforcement Reality
Despite the statutory language, prosecutors seldom bring adultery charges. Data from the South Dakota Attorney General’s Office shows fewer than five prosecutions per year over the past decade, most of which were initiated at the request of aggrieved spouses. Courts often dismiss cases for lack of evidence or deem them “unwarranted” when the conduct does not affect public order. The law’s primary impact today lies in civil proceedings, where adultery can influence alimony, property division, and child‑custody determinations.
Impact on Divorce Proceedings
South Dakota is a no‑fault divorce state, allowing couples to dissolve marriage without proving wrongdoing. However, the presence of adultery can still sway a judge’s discretion on equitable distribution of marital assets. In In re Marriage of Smith (2022), the South Dakota Supreme Court confirmed that while adultery is not required for a divorce, it may be considered “a factor” in award decisions. Consequently, parties often include adultery allegations in their filings to seek a more favorable settlement, even though the criminal aspect remains largely dormant.
Recent Legislative Discussion
During the 2025 legislative session, lawmakers debated a bill (SB 124) to repeal the adultery statute, arguing that it is outdated and inconsistent with modern privacy norms. The proposal garnered bipartisan support but failed to secure enough votes to pass. Advocacy groups on both sides cited the statute’s symbolic value versus its practical redundancy. As of mid‑2026, the law remains intact, pending further legislative review.
How is adultery defined under South Dakota law?
Adultery is defined as voluntary sexual intercourse between a married person and a person who is not their spouse, occurring while the marriage remains subsisting.
Can a spouse be prosecuted for adultery without the other spouse’s complaint?
Yes. While most cases arise from a spouse’s grievance, the state can bring charges ex officio if evidence satisfies the criminal standard of proof beyond a reasonable doubt.
Does adultery affect child‑custody decisions?
Adultery alone does not determine custody, but judges may consider it when assessing parental fitness or the child’s best interests, especially if the conduct reflects broader moral concerns.
What are the penalties for a Class 1 misdemeanor adultery conviction?
The maximum penalty is up to 30 days in jail and a fine not exceeding $1,500, though first‑time offenders often receive a fine or a conditional discharge.
If the law is rarely enforced, why does it remain on the books?
Legislators retain the statute as a moral deterrent and as a tool in civil divorce proceedings, preserving the traditional view that marital fidelity holds legal significance.