Central to the calculation of a federal criminal defendant’s sentence under the United States Sentencing Guidelines (Guidelines) is the defendant’s “relevant conduct.” That term, while encompassing conduct found by a jury or admitted by the defendant, can also include conduct that was not charged, as well as the conduct underlying charges of which the defendant was acquitted. The lower federal courts have almost uniformly approved of the use of acquitted or uncharged conduct at sentencing, so long as a judge finds by a preponderance of the evidence that the conduct occurred. The Supreme Court has also held that the use of acquitted conduct pursuant to the Guidelines presents no double jeopardy issue under the Constitution. Judicial fact-finding at sentencing has not been without its critics, however; legal commentators and multiple Justices have expressed misgivings about the continued judicial reliance on such conduct to increase sentencing ranges under the Guidelines, largely focusing on the constitutional right to a jury trial. In fact, both of President Trump’s nominees to the Supreme Court— Justice Gorsuch and, most recently, Judge Brett Kavanaugh of the United States Court of Appeals for the D.C. Circuit— have suggested during their tenures as Circuit judges that they may view judicial fact-finding at sentencing to be constitutionally problematic. Two bills have also recently been introduced in the House of Representatives that would alter the practice legislatively. Given the possibility of judicial or legislative changes in this area of criminal sentencing law, this Sidebar provides an overview of the issue by briefly describing the use of relevant conduct under the Guidelines and tracing the Supreme Court case law that has informed the practice, before addressing judicial commentary and recently proposed legislation regarding the use of acquitted or uncharged conduct at sentencing….