In Colorado v. Connelly, the U.S. Supreme Court ruled that a defendant's confession cannot be excluded from evidence on the grounds of being involuntary unless there is proof of government coercion or misconduct in obtaining it. Francis Barry Connelly approached a police officer in Denver and confessed to committing murder a year earlier without any prompting by law enforcement officials. Despite his history of chronic schizophrenia, he was found competent to stand trial but later argued that his mental condition made his confession involuntary and thus should not have been admitted as evidence during trial proceedings. The Supreme Court disagreed with this argument, stating that coercive police activity is necessary for a finding of involuntariness under due process clause protections against self-incrimination.

In the dissenting opinion for Colorado v. Connelly, Justice Brennan argued that the majority's decision to focus solely on police coercion in determining whether a confession is voluntary overlooks other factors that can impact a suspect's ability to make an informed and free choice. He contended that mental illness could also impair a person’s capacity to voluntarily confess, even without any coercive action from law enforcement officers. In this case, Francis Connelly had confessed to murder while suffering from chronic schizophrenia and was not under any immediate pressure or influence by police officers at the time of his confession. Brennan believed it was wrong for the court majority to ignore these circumstances when considering if his confession should be admissible as evidence in court proceedings.