Whether the Constitution permits courts to subject evidence of third-party guilt to heightened relevance standards

QUESTION PRESENTED This Court has long held that a criminal defendant has a constitutional right to introduce evidence suggesting that someone else committed the crime charged. In Holmes v. South Carolina, 547 U.S. 319 (2006), the Court affirmed that trial courts may exclude such evidence under neutral balancing principles, such as that contained in Federal Rule of Evidence 403. But the Constitution does not tolerate evidentiary rules that do not “rationally serve” the permissible goal of “focus[ing] the trial on the central issues by excluding evidence that has only a very weak logical connection to the central issues.” Holmes, 547 USS. at 330. The lower courts have divided as to the meaning of Holmes. Some courts have concluded that Holmes prohibits application of rules that apply heightened standards of relevance to evidence of third-party guilt. That is, these courts hold that, under Holmes, while evidence of third-party guilt is certainly subject to normal evidentiary rules, it cannot be disfavored, with more exacting standards for its admission. Other courts, however, have created special rules for evidence of third-party guilt, requiring heightened showings of relevance prior to its admission. Here, the lower courts applied a heightened standard, and thus denied petitioner’s request to introduce evidence of third-party guilt. They did so even though, just a few years earlier, another court had granted a search warrant based on that same evidence, finding it satisfied the probable cause standard. The question presented is: Whether the Constitution permits courts to subject evidence of third-party guilt to heightened relevance standards.