In January 1983, Roberts wrote a memo that highlighted a recent National Institute of Justice study on the effect of the exclusionary rule. (The exclusionary rule, the judicially crafted remedy for violations of the Fourth Amendment, generally bars illegally obtained evidence from being admitted.) According to Roberts’s memo, “the study shows that the exclusionary rule resulted in the release of 29% of felony drug arrestees in Los Angeles in one year—a far cry from the highly misleading 0.4% figure usually bandied about.” Roberts concludes: “This study should be highly useful in the campaign to amend or abolish the exclusionary rule.”