[JURIST] The US Supreme Court [official website; JURIST news archive] on Monday reversed [opinion, PDF] a decision by the US Court of Appeals for the Eleventh Circuit [official website] that had affirmed a death sentence for a veteran convicted of murder who suffered from post-traumatic stress disorder (PTSD) [NIMH backgrounder]. In Porter v. McCollum [docket], George Porter, a decorated Korean War veteran, had argued that he had been improperly sentenced to die because his counsel failed to present evidence of factors that would mitigate such a sentence in violation of his Sixth Amendment [text] right to counsel. Following a district court ruling that Porter's counsel was ineffective, the court of appeals reversed, holding that the district court did not give proper deference to the state court that issued Porter's sentence. In an unsigned per curiam opinion, the Court reversed the Eleventh Circuit's decision, holding that Porter's representation was deficient and that the deficiency had prejudiced Porter:

It is unquestioned that under the prevailing professional norms at the time of Porter's trial, counsel had an "obligation to conduct a thorough investigation of the defendant's background." The investigation conducted by Porter's counsel clearly did not satisfy those norms. … The decision not to investigate did not reflect reasonable professional judgment.

We do not require a defendant to show "that counsel's deficient conduct more likely than not altered the outcome" of his penalty proceeding, but rather that he establish "a probability sufficient to undermine confidence in that outcome." This Porter has done.

The Court emphasized that Porter's military service could have provided evidence of a mitigating circumstance: "the relevance of Porter's extensive combat experience is not only that he served honorably under extreme hardship and gruesome conditions, but also that the jury might find mitigating the intense stress and mental and emotional toll that combat took on Porter."

Porter was convicted in Florida of murdering his ex-girlfriend and her boyfriend in 1988. After pleading guilty and receiving the death penalty, Porter directly appealed the sentence to the Flordia Supreme Court [official website] in 1990, but the ruling was affirmed. In 1995, Porter filed a petition for post-conviction relief in state court based on the position that his counsel failed to properly investigate and present mitigating evidence during the sentencing phase of his trial. During that hearing Porter was able to present evidence of child abuse, substance abuse problems, mental health issues, and his military service and the trauma he suffered during that time.