Justice Samuel Alito wrote his first opinion for the U.S. Supreme Court in Holmes v. South Carolina (2006). Ironically, Alito, a former federal prosecutor, wrote an opinion that protected the constitutional rights of Bobby Lee Holmes, a criminal defendant who was prevented by South Carolina state courts from introducing evidence that another person committed the crime.

The South Carolina Supreme Court had ruled that the trial judge did not need to allow the defendant to present evidence of third-party guilt if the prosecution had strong forensic evidence showing the defendant’s guilt.

Alito and the rest of the U.S. Supreme Court disagreed, writing that it violated the defendant’s right to present a complete defense. “The true strength of the prosecution’s proof cannot be assessed without considering challenges to the reliability of the prosecution’s evidence,” he wrote.