From the Document: "Two sets of authorities govern proceedings in federal court: 'substantive' laws create certain legal rights or impose duties, while 'procedural' laws control the way courts enforce those substantive rights or duties. While many are aware of Congress's role in enacting and the courts' role in interpreting substantive laws, casual observers may be less conscious of the procedural rules that apply in federal litigation. Nonetheless, the various procedures governing federal civil and criminal cases are important. Indeed, in some instances, a claim may succeed or fail based on a party's compliance with the required procedures. Congress enjoys ample authority to establish and structure lower federal courts. And, as the Supreme Court has stated, 'the constitutional provision for a federal court system (augmented by the Necessary and Proper Clause) carries with it congressional power to make rules governing the practice and pleading in those courts.' However, recognizing that the courts themselves possess significant expertise in crafting such rules, Congress passed the Rules Enabling Act, codified at Sections 2071-2077 of Title 28 of the U.S. Code. The Rules Enabling Act grants the Supreme Court primary authority for creating and amending federal procedural rules, but also imposes congressional oversight of the rulemaking process. This In Focus summarizes the authorities that govern federal judicial procedure, outlines the rulemaking process under the Rules Enabling Act, and presents related considerations for Congress."
CRS In Focus, IF11557
Congressional Research Service: https://crsreports.congress.gov/