Defenses and Evidence Rules in Minnesota Criminal Sexual Conduct Cases

The Rape-Shield Law (Minn. Stat. § 609.347 and Rule 412)

Minnesota's rape-shield law sharply limits the use of evidence about a complainant's prior sexual history. As a general rule, evidence of the victim's previous sexual conduct is not admissible, subject to narrow statutory exceptions. One recognized exception, for example, allows evidence of specific prior conduct in limited circumstances such as showing the source of semen, pregnancy, or disease. Courts also must weigh a defendant's constitutional confrontation rights, but the default strongly favors exclusion.

What this means for you: The instinct to "put the complainant's history on trial" generally won't work in Minnesota. Effective defense focuses elsewhere — on the elements, the evidence of the specific incident, and the reliability of the allegation.

Two Rules That Favor the Prosecution

Minnesota law contains two provisions defendants are often surprised by:

• No corroboration required. The testimony of the complainant need not be corroborated. A case can proceed — and result in a conviction — on the complainant's testimony alone, without physical evidence or additional witnesses.
• No resistance required. The state does not have to show that the complainant physically resisted.

Defenses That No Longer Exist

This is critical, because outdated sources still describe defenses that Minnesota has eliminated:

• The "voluntary relationship" / marital exception is gone. Former § 609.349, which shielded certain conduct between spouses or cohabiting partners, was repealed in 2019. Marriage or an ongoing relationship is not a defense.
• Consent is not a defense to age-based charges. Where a charge rests on the complainant's age, the complainant's consent is not a defense.
• Mistake about age is not a defense for most age-based charges — with one narrow statutory exception for third- and fourth-degree charges involving a 14- or 15-year-old complainant, explained in detail below.

Defenses That May Be Available

Depending entirely on the facts, defenses in a CSC case can include:

• Consent — in cases not based on age or incapacity, whether there was a freely given present agreement (as the statute defines consent) is often the central dispute.
• The conduct didn't occur / mistaken or false allegation — challenging whether the act happened or whether this defendant was involved.
• Identity — particularly where identification is uncertain.
• Failure of proof on a specific element — for example, the absence of force, coercion, injury, a qualifying relationship, or the required age gap.
• Constitutional challenges — such as unlawful search, interrogation, or identification procedures, which can lead to suppression of evidence.
• The medical-purposes exclusion (§ 609.348) — the CSC statutes do not apply to legitimate medical procedures.

The Mistake-of-Age Affirmative Defense: A Narrow but Real Exception

Minnesota law is often summarized as "mistake of age is never a defense." That summary is wrong. For two specific charges, in one narrow age band, the Legislature has written a genuine affirmative defense into the statute — and understanding exactly where it applies, and where the age gap becomes too wide for it to matter, can be decisive.

An affirmative defense is different from arguing the state failed to prove its case. Here, the conduct and the age may be admitted, but the law provides a defense that the defendant must prove by a preponderance of the evidence: that the actor reasonably believed the complainant was 16 years of age or older. The burden is on the defense, not the state.

This defense exists only within a specific window. Below the age gap that triggers the crime, there is no offense at all. Above 60 months (five years), the defense disappears entirely. It lives only in between — and only for third- and fourth-degree charges based on a 14- or 15-year-old complainant.

Two points that are true across every one of these: the complainant's consent is never a defense in an age-based case, regardless of the age gap; and the mistake-of-age defense, where it exists, is never satisfied simply by the complainant saying they were older — the belief must be reasonable, and the defendant carries the burden of proving it.

An area in flux: the statutory limits on the mistake-of-age defense have been challenged on constitutional (equal-protection) grounds, on the theory that cutting off the defense based on the actor's age treats similarly situated defendants differently. This is unsettled and the law here can change, so the current statute should always be checked against the latest decisions.

Statute of Limitations

Minnesota has expanded the time allowed to bring CSC charges, and for some offenses the time limit has been eliminated entirely. Because the rules depend on the offense, the date, and the facts, the limitations period in any particular case should be checked carefully rather than assumed.

Victim Identity Confidentiality (Minn. Stat. § 609.3471)

Certain records that could reveal the identity of a victim are confidential, which affects how information is handled during a case.

Key Terms

• Rape-shield law: The rule (§ 609.347 / Rule 412) generally barring evidence of a complainant's prior sexual conduct.
• No-corroboration rule: The complainant's testimony need not be corroborated.
• Repealed marital exception: The former voluntary-relationship defense, eliminated in 2019.
• Suppression: Excluding evidence obtained in violation of constitutional rights.
• Affirmative defense: A defense the defendant must raise and prove (here, by a preponderance of the evidence), rather than one the state must disprove.
• Mistake-of-age defense: The narrow affirmative defense, available only for third- and fourth-degree charges with a 14- or 15-year-old complainant and an actor no more than 60 months older, that the actor reasonably believed the complainant was 16 or older.