Balancing Act: Admissibility of Propensity Evidence Under Article I, Section 18(c) of the Missouri Constitution

The American legal system has a long-standing ban against using character evidence to show a party’s propensity to act in conformity with that character. This rule has been especially stringent in the criminal system, where the notion is that when a criminal defendant is tried for a crime, that defendant should face trial only for the crimes charged. However, certain crimes, like sex crimes, can be incredibly difficult to prosecute and, accordingly, victim advocates have pushed for changes to these rules. The Federal Rules of Evidence (“FRE”) and several states have enacted rules that allow evidence of prior bad acts to be used as propensity evidence in prosecutions of sex crimes.

In 2014, Missouri voters enacted a similar rule for prosecutions of child sex abuse cases by amending the Missouri Constitution.