In those cases, the legislature passed a specialized statute broadening the type of "prior bad acts" that can be admitted in a sexual assault trial. [Note: usually, the evidence must focus on the actual alleged assault, and not on what the accused may or may not have done in the past.] The general evidentiary rule, MRE 404(b), has a series of safeguards that must be met prior to introducing "prior bad acts" collateral to the charged conduct.
For example, the prosecution cannot simply introduce the evidence in order to demonstrate to a jury that the defendant, in the charged case, was acting within his propensity. Rather, the collateral evidence must be limited to showing that the accused was acting in accord to a pattern or a plan. If the events were distinct, most trial court judges would preclude introduction of such evidence.
Even when the judges allowed such evidence, it was introduced with a cautionary instruction to the jury.
Not so with the statute, MCLA 768.27a. That statute, specially applicable to sexual assault cases, allows evidence of "prior bad acts" that have any relevance or bearing on the charged offense. It is much easier for the prosecutor to introduce such evidence in an sexual assault trial.
In the People v Watkins case, the Michigan Supreme Court, recognizing the irresolvable conflict between the evidentiary rule and the statute, held that the statute controls. Now, prosecutors can introduce evidence of such prior bad acts, shifting the focus of what actually happened in the charged offense, to what happened in other situations, under other circumstances.
One of the problems with the evidence in the companion case to Watkins was that the evidence being introduced was 20-years old. The trial court had a problem with that, finding the evidence more prejudicial than probative under MRE 403. This too, was reversed by the Supreme Court, which held that the trial courts now have to focus on the probative value of the evidence, not on its prejudicial nature. Essentially, this throws the balance test long-utilized by trial courts, out the window.
The dissent in this case [Justice Marilyn Kelly] was troubled that the Legislature seemed to be usurping powers which Michigan's constitution bestowed on the judiciary: i.e. the power to rule on the admissibility of evidence at a trial. Justice Kelly also called out the majority on the intellectual honesty of the majority opinion in addressing MRE 403, and on its largely unanalyzed conclusion that the trial court committed an "abuse of discretion" in precluding the evidence in the Pullen case.
Sexual assault cases, already tough to defend, have now been made much more difficult with this decision. If defense counsel is lucky, the case will not involve things that her client did years before; just a straightforward presentation of evidence and cross examination on the charged offense.