Involuntary commitment is governed by state law and procedures vary from state to state. In some jurisdictions, laws regarding the commitment of juveniles may vary, with what is the de facto involuntary commitment of a juvenile perhaps de jure defined as "voluntary" if his parents agree, though he may still have a right to protest and attempt to get released. However, there is a body of case law governing the civil commitment of individuals under the Fourteenth Amendment through U.S. Supreme Court rulings beginning with Addington v. Texas in 1979 which set the bar for involuntary commitment for treatment by raising the burden of proof required to commit persons from the usual civil burden of proof of "preponderance of the evidence" to the higher standard of "clear and convincing" evidence.
In 1975, the U.S. Supreme Court ruled that involuntary hospitalization and/or treatment violates an individual's civil rights in O'Connor v. Donaldson. This ruling forced individual states to change their statutes. For example, the individual must be exhibiting behavior that is a danger to himself or others in order to be held, the hold must be for evaluation only and a court order must be received for more than very short term treatment or hospitalization (typically no longer than 72 hours). This ruling has severely limited involuntary treatment and hospitalization in the U.S. In the U.S. the specifics of the relevant statutes vary from state to state.
An example of involuntary commitment procedures is the Baker Act used in Florida. Under this law, a person may be committed only if they present a danger to themselves or others. A police officer, doctor, nurse or licensed mental health professional may initiate an involuntary examination that lasts for up to 72 hours. Within this time, two psychiatrists may ask a judge to extend the commitment and order involuntary treatment. The Baker Act also requires that all commitment orders be reviewed every six months in addition to ensuring certain rights to the committed including the right to contact outsiders. Also, a person under an involuntary commitment order has a right to counsel and a right to have the state provide a public defender if they cannot afford a lawyer. While the Florida law allows police to initiate the examination, it is the recommendations of two psychiatrists that guide the decisions of the court.