Until 1868, a defendant in a criminal trial in Minnesota could not testify in his own defense. Like other states, Minnesota adhered to the common law rule that barred a criminal defendant from testifying because he had an "interest" in the outcome of the trial. The parallel common law prohibition against civil parties from testifying was never followed in Minnesota. On March 6, 1868, the Minnesota Legislature amended the witness competency law to permit a criminal defendant to testify if he chose.
This article describes how the supreme court, during the territorial era and after statehood, strictly applied the common law bar, the reform movement that influenced the state legislature to liberalize the witness competency law, and subsequent court interpretations of that legislation. It concludes with an explanation of why defendants in the Dakota War trials in the autumn of 1862 were permitted to speak at length, explain their behavior, refute witnesses and offer alibis to the military commission.
Excerpts from three decisions of the Minnesota Supreme Court and the transcripts of eleven Dakota War trials are posted in an Appendix.