In Addington v. Texas (1978), the U.S Supreme Court ruled that a state cannot commit an individual for involuntary mental health treatment unless there is "clear and convincing" evidence of their need for such care. The case arose when Thomas H. Addington was involuntarily committed to a state hospital in Austin, Texas, after being diagnosed with paranoid schizophrenia. His commitment was based on the standard of proof known as preponderance of the evidence, which means it's more likely than not that he needed treatment. However, Addington argued this violated his constitutional rights under the Fourteenth Amendment’s due process clause because it allowed for indefinite confinement based on minimal proof. The court agreed with him in a 5-4 decision stating that while states have legitimate interests in providing care to those who are unable to take care of themselves and protecting community from potential dangers posed by some mentally ill individuals; these interests do not outweigh significant liberty interest person has avoiding forced confinement.

In the dissenting opinion for Addington v. Texas, Justice William H. Rehnquist argued that the majority's decision to require a "clear and convincing" standard of proof in civil commitment proceedings was an unnecessary departure from traditional state practices. He contended that states should have flexibility in determining their own standards of proof based on their unique circumstances and needs, rather than being bound by a uniform federal rule. Furthermore, he expressed concern about the potential implications of this ruling on other areas of law where states traditionally had discretion to set their own evidentiary standards such as juvenile delinquency proceedings or paternity suits. In his view, there was no constitutional basis for imposing such stringent requirements on states' ability to protect both public safety and individual rights through civil commitment procedures.