As Chief Justice John Marshall stated in Marbury v. Madison : "It is emphatically the province and duty of the judicial department to say what the law is." Judges subscribing to these theories may employ different interpretive tools to discover Congress's meaning, looking to the ordinary meaning of the disputed statutory text, its statutory context, any applicable interpretive canons, the legislative history of the provision, and evidence about how the statute has been or may be implemented. To help provide Congress with a general understanding of how courts interpret statutory languge, this report begins by discussing the general goals of statutory interpretation, reviewing a variety of contemporary and historical approaches. The report then describes the two primary theories of interpretation employed today, before examining the main types of tools that courts use to determine statutory meaning. The report concludes by exploring developing issues in statutory interpretation. . . public policy" to the specific circumstances before the court. The predominant view of a judge's proper role in statutory interpretation is one of "legislative supremacy." Major Theories of Statutory Interpretation

The two predominant theories of statutory interpretation today are purposivism and textualism. Consequently, a judge's interpretive theory might influence which tools she uses. Ordinary Meaning

Courts often begin by looking for the "ordinary" or "plain" meaning of the statutory text. To gather evidence of statutory meaning, a judge may turn to the rest of the provision, to the act as a whole, or to similar provisions elsewhere in the law. To the extent that the substantive canons suggest that a judge should read a statute in a way that is not immediately evident from the statute's text or purpose, both textualists and purposivists may be wary of employing these canons. By contrast, many textualists argue that legislative history should be used sparingly. But, based on the statutory context and the "broader structure of the Act," the Court concluded that a strict textualist approach to interpreting the statute was not the best reading of the statute.
In the tripartite structure of the U.S. federal government, it is the job of courts to say what the law is, as Chief Justice John Marshall announced in 1803. When courts render decisions on the meaning of statutes, the prevailing view is that a judge's task is not to make the law, but rather to interpret the law made by Congress. The two main theories of statutory interpretation—purposivism and textualism—disagree about how judges can best adhere to this ideal of legislative supremacy. The problem is especially acute in instances where it is unlikely that Congress anticipated and legislated for the specific circumstances being disputed before the court. While purposivists argue that courts should prioritize interpretations that advance the statute's purpose, textualists maintain that a judge's focus should be confined primarily to the statute's text.
Regardless of their interpretive theory, judges use many of the same tools to gather evidence of statutory meaning. First, judges often begin by looking to the ordinary meaning of the statutory text. Second, courts interpret specific provisions by looking to the broader statutory context. Third, judges may turn to the canons of construction, which are presumptions about how courts ordinarily read statutes. Fourth, courts may look to the legislative history of a provision. Finally, a judge might consider how a statute has been—or will be—implemented. Although both purposivists and textualists may use any of these tools, a judge's theory of statutory interpretation may influence the order in which these tools are applied and how much weight is given to each tool.
This report begins by discussing the general goals of statutory interpretation, reviewing a variety of contemporary as well as historical approaches. The report then briefly describes the two primary theories of interpretation employed today, before examining the main types of tools that courts use to determine statutory meaning. The report concludes by exploring developing issues in statutory interpretation.