HEY, I'VE GOT A GREAT IDEA: Let's pack the Supreme Court.
Hint: IQ isn't additive. Also I recall reading somewhere that a committee is just as smart as it's dumbest member.
More: "Certainly groups comprising more than eight or nine people are inefficient because they allow some members to coast (‘social loafing’), and their size allows cliques and sub-teams to form, each with their own agenda, which can derail the outcome." I would think 19 would more than sufficient to screw things up.