The Sherlock Holmes Canon

Many of the Supreme Court’s statutory interpretation cases infer meaning from Congress’s failure to comment in the legislative record. Colorfully referred to as the “dog that did not bark” canon, after a Sherlock Holmes story involving a watchdog that failed to bark while a racehorse was being stolen, the interpretive presumption holds as follows: if a statutory interpretation would significantly change the existing legal landscape, Congress can be expected to comment on that change in the legislative record; thus, a lack of congressional comment regarding a significant change can be taken as evidence that Congress did not intend that interpretation. Failure to comment arguments typically arise when the Supreme Court considers the meaning of a statutory provision that has been amended and an interpretation is advanced that arguably would change the status quo. Surprisingly, this canine canon of construction has received little theoretical attention — and what little attention it has received has tended to be positive, assuming that the canon leads courts to follow congressional intent. But there are several practical and theoretical problems with the assumptions underlying the canon. This essay examines how courts employ the Sherlock Holmes canon in practice and explores the canon’s normative and theoretical implications in detail. Ultimately, it argues that the Sherlock Holmes canon should be invoked only in rare cases, when there is special reason for courts to expect or require Congress to comment on a change in the law.