TIM O'BRIEN, guest anchor: The shooting spree at Virginia Tech last April that left 33 people dead -- including the shooter -- has revived a the long-simmering debate over the treatment of the mentally ill and how to balance societyís need to protect itself against an individuals right to be left alone. Why was Seung-Hui Cho on the street rather than in a mental hospital given his long history of mental problems? The U.S. Supreme Court ruled 15 years ago that authorities need only show a person is mentally ill and a threat to himself or others to be committed. But Virginia and a handful of other states has a much higher standard. In Virginia, authorities must show not only a danger but that the danger is imminent before one may be involuntarily put away. Might a lesser standard have prevented the Virginia Tech massacre? Some mental health advocates contend it would only make matters worse. Our correspondent is Lucky Severson.

LUCKY SEVERSON: It was the deadliest shooting in American history, and there are still more questions than answers about what went so terribly wrong. How was it that this young man Seung-Hui Cho was able to slip through the system even though authorities suspected he presented ìan imminent dangerî to himself or others as a result of mental illness?

After the shooting, the Virginia task force on commitment went to work with a new sense of urgency, struggling over Virginiaís tough standard for committing someone to a mental hospital. It requires finding a mental patient imminently dangerous before he or she can be involuntarily committed. A law with a lower bar might have forced the killer into a mental institution for treatment and prevented the horror.

PETE EARLEY (Author, CRAZY, during task force meeting): When do we force someone against their will and say itís in societyís best interest to step in and commit you?

MICHAEL ALLEN (Attorney, Relman & Dane PLLC, during task force meeting): Iím entirely comfortable with Virginiaís imminent danger standard.

Mr. EARLEY: Okay, why are you comfortable with that?

Mr. ALLEN: Because I think it appropriately balances the stateís ability to protect others and individual rights and liberty on the other.

SEVERSON: When and when not to commit is a deeply personal subject to Pete Earley. Heís the author of several books on crime and punishment and wrote one in particular about his son Mike, who developed a bipolar disorder in his twenties. The father asked that we not show pictures of his son, who was eventually hospitalized, put on medication, and seemed to be getting better. Then one day Pete got a call saying that Mike had gone crazy.

Mr. EARLEY: So I raced to New York, and the car ride from New York to Virginia was unbelievable. He would laugh one minute, and heíd start sobbing the next. And I pleaded with him to take his medication and I thought, well, the doctors would know what to do. He said to me, ìDad, how would you feel if someone you loved killed himself?î So we raced to the emergency room, and the intake nurse, I remember, rolled her eyes as he was telling her that God was giving him secret messages.

SEVERSON: He says they waited in the emergency room for four hours and, getting desperate, he raced outside and flagged down a doctor.

EARLEY: I will never forget how he came in. He came in with his hands raised, as if he was surrendering, and he said, ìIím not going to be able to help your son.î And I said, ìYou havenít even examined him! He told me that he was thinking about killing himself.î And the doctor said, ìLook, Virginia law is very specific. Unless a personís an imminent danger either to himself or someone else, we canít intervene.î And the doctor turned to me, and he said, ìBring him back when he tries to kill himself or he tries to kill you.î

SEVERSON: Pete still gets upset when he recounts how he took his son home and watched him sink into what he called a mental abyss.

Mr. EARLEY: At one point he had tin foil wrapped around his head to keep the CIA from reading his thoughts through the TV station. He slipped out of the house. He broke into a neighborís house to take a bubble bath and luckily they werenít there.

SEVERSON: Police told Pete that unless he said his son had threatened to kill him or himself he would be sent to jail for breaking in the neighborsí house, rather than a mental hospital.

Mr. EARLEY: So I went in and I lied and I said Mike had threatened to kill me, and that was good enough to get him into the hospital. And 48 hours later, he voluntarily committed himself

SEVERSON (to Mr. Allen): What would you do in Pete Earleyís situation? Would you have lied?

Mr. ALLEN: I suspect, in the end, if I were desperate to help my son or daughter, and none of the other interventions had worked, that Iíd be temped to do that.

SEVERSON: Michael Allen is an outspoken advocate of the rights and civil liberties of mental patients, and he strongly supports Virginiaís ìimminent dangerî standard. He says to lower the threshold would do more harm than good to the 54 million Americans the government says suffer from various symptoms of mental illness.

Mr. ALLEN: It will have the effect, literally, of pushing people out of the system -- that is, if you begin to worry that showing up voluntarily for services will end up with some sort of court order requiring you to do something, you may simply stay under the bridge and not come in and not connect to the system at all.

SEVERSON: But the system failed in Virginia even after Cho was ordered by a judge to get involuntary outpatient treatment. He didnít show up, and mental health officials didnít follow through. Critics say in many states thereís no follow-through because of lack of funding.

Mr. EARLEY: Look at Virginia Tech: ìWell, we couldnít do anything because he didnít hurt anyone.îThatís what the professor said. ìOh, we couldnít do anything,î the police said, ìuntil he hurts someone.î You know, itís become a good excuse not to provide people with mental health services.

SEVERSON: Historically mental patients were committed to large institutions like St. Elizabethís here in Washington, D.C. In its heyday, St. Elizabeth treated 7,000 patients. Today that number has shrunk to just over 300. Thatís because in the '70s and '80s, patients were moved out of the big mental hospitals. The plan was they would be treated by community-based programs.