They have some interesting rules up in Minnesota. 2 things jump out at me. While I caution that I have not watched this trial— and barely have an armchair opinion about this officer’s culpability; Generally speaking. expert witnesses in most jurisdictions are not supposed to testify about the ultimate issue in the trial. of course there are exceptions, and the defense perhaps opened the door to this expert’s testimony. But, there are 12 people sitting nearby who, given the tools for decision making, will apply their collective wisdom. they will decide whether a shooting was criminal or justifiable. Or negligent, or whatever. Professor Stoughton of the University of South Carolina Law School testified that the use of deadly force "was not appropriate, and the evidence suggests a reasonable officer in Kim Potter's position could not have believed it was proportional to the threat at the time". Stoughton has now arguably become a “super-juror”.
But at the risk of “burying the lead” — most troubling from the perspective of a litigator, is this “spark of life” testimony. As pointed out by Andrew Leonatti in a blog post on April 12, 2021 for Thomson Reuters: In Minnesota, however, prosecutors are allowed to call these "spark of life" witnesses. In 1985 the Minnesota Supreme Court upheld a murder conviction. The defense had argued that the prosecutor unfairly prejudiced the jury in making an emotional speech about the life of the victim. The court held:
While it is true that the quality or personal details of the victim's life are not strictly relevant to the issue ... the victim was not just bones and sinews covered with flesh, but was imbued with the spark of life. The prosecution has some leeway to show that spark and present the victim as a human being as long as it is not an attempt to invoke any undue sympathy or inflame the jury's passions.
From the moment the jury is empaneled, a criminal trial judge goes to great lengths to minimize the emotional aspects of the trial. This is the foundation upon which nearly all of the rules of evidence are based: objectivity, equity, fairness, neutrality, and the very integrity of the verdict spring from this never-ending attempt to mitigate the impact of juror emotions. Fortunately, I have quite a number of friends and colleagues from the legal community up in Minnesota. Perhaps they can explain what the heck is going on.