The Federal Rules of Civil Procedure (officially abbreviated Fed. R. Civ. P.; colloquially FRCP) govern civil procedure in United States district courts. They are the companion to the Federal Rules of Criminal Procedure. Rules promulgated by the United States Supreme Court pursuant to the Rules Enabling Act become part of the FRCP unless, within seven months, the United States Congress acts to veto them. The Court's modifications to the rules are usually based upon recommendations from the Judicial Conference of the United States, the federal judiciary's internal policy-making body.
At the time 28 U.S.C. § 724 (1934) was adopted, federal courts were generally required to follow the procedural rules of the states in which they sat, but they were free to apply federal common law in cases not governed by a state constitution or state statute. Whether within the intent of Congress or not when adopting 28 U.S.C. 724 (1934), the situation was effectively reversed in 1938, the year the Federal Rules of Civil Procedure took effect. Federal courts are now required to apply the substantive law of the states as rules of decision in cases where state law is in question, including state judicial decisions, and the federal courts almost always are required to use the FRCP as their rules of civil procedure. States may determine their own rules, which apply in state courts, although 35 of the 50 states have adopted rules that are based on the FRCP.
