In all state and federal jurisdictions in the United States, joinder allows prosecutors to join multiple offenses against a criminal defendant. Joinder pervades the American criminal justice system, and some jurisdictions see joinder in more than half of their cases. Most states and the federal courts use a liberal joinder system where courts may join offenses regardless of their severity or punishment. These systems derive from judicial efficiency arguments, seeking to avoid unnecessary trials and striving to conserve time, money, and other resources. In a liberal joinder regime, the court may force a defendant to prepare for a trial in which she must simultaneously defend against a misdemeanor offense, like possession of marijuana, and a capital felony offense with a potential death sentence—even though the two charges may require completely different defense strategies. Jurisdictions should no longer broadly protect the joinder of all types of offenses in the name of judicial efficiency or juridical discretion. Instead, jurisdictions should categorically protect defendants charged with capital offenses from the potentially prejudicial nature of joinder, as Louisiana has for nearly a century. Born from the state’s unique judicial history, Louisiana’s joinder regime restricts joinder to those offenses which are triable by the same “mode of trial,” a phrase that has undergone statutory interpretation, constitutional examination, and judicial scrutiny. Louisiana offers its criminal defendants a structural, procedural protection by prohibiting the joinder of capital offenses with noncapital offenses. Although other scholars have published articles and studies criticizing joinder regimes, pointing out the ways in which offenses’ joinder may prejudice defendants, or presenting data to show prejudice’s existence in practice, none have yet suggested—as this Article does—that jurisdictions revise their joinder regimes to prohibit the joinder of capital and noncapital offenses. If jurisdictions revised their joinder schemes in this way, they could maintain liberal joinder regimes for the most common criminal cases, where joinder is most efficient, without continuing to hinder those defendants who face the most serious consequences and the highest stakes during their trials. This Article first discusses the history and current status of joinder in most jurisdictions, followed by the history and current status of joinder in Louisiana. It then explains capital-offense joinder in Louisiana and how it differs from other jurisdictions in the United States. The Article further analyzes the arguments for liberal joinder and critiques them by presenting research in the field, practical considerations, and historical arguments. The Article concludes by urging other jurisdictions, particularly those with capital sentencing capabilities or capital offense punishments, to amend their joinder provisions to prevent the joinder of capital offenses with noncapital offenses. If jurisdictions revised their joinder schemes in this way, they could maintain liberal joinder regimes for the most common criminal cases, where joinder is most efficient, without continuing to hinder those defendants who face the most serious consequences and the highest stakes during their trials.