On February 8, 2000, William Anthony Miller, a homeless man who suffered from mental illness, was shot to death for lunging at police with a tree branch. In the view of some commentators, this incident and others like it demonstrate that laws need to be strengthened to allow the seriously mentally ill to be committed to hospital care.

Before the 1960s, most of the seriously mentally ill resided in state hospitals. However, after it was discovered that many mental illnesses could be treated with medication, policymakers reasoned that patients would be better served through outpatient care. The process of deinstitutionalization, which occurred during the 1960s and 1970s, led to the release of over eight hundred thousand mentally ill patients from institutions. Many of these released patients, too debilitated to seek care, became homeless.

Consequently, opponents of deinstitutionalization maintain that some of the...