The Japanese government has decided on a controversial "compulsory preventive confinement" measure for drug addicts and mental patients involved in serious crimes.
Legislation is expected to be submitted to parliament shortly.
But the proposal has already been attacked by legal and medical professional groups, who are concerned it could lead to serious violations of human rights.
The government has taken this step to combat an upsurge in random killings and assaults on innocent pedestrians on city streets in the daytime. The majority have been committed by habitual users of stimulant drugs.
This upsurge of violence has come as a great shock to a nation that prides itself on the safety of its city streets, even at midnight.
The worst case occurred in June, when a supposedly cured addict killed two women and two small children on a quiet suburban Tokyo street because, in his words, "They looked so happy." The assailant also said he was a "samurai warrior" whose victims should have been proud to die at his hands.
Even as the Cabinet was considering the confinement measure, another drug addict took two people hostage in a Tokyo bakery. He was quickly subdued by police.
The National Police Agency reports more than a dozen motiveless street killings so far this year, plus an equal number of woundings.
Taro Nakayama, head of the government committee that produced the proposed legislation, said it was necessary to crack down on drug use and impose stronger penalties to protect the public from random violence.
"The public has a right to expect protection from those elements of society addicted to drugs or whose mental problems lead them to violence," he said.
The proposed preventive confinement would apply to confirmed drug addicts and mental patients with a history of serious crimes. It would affect those who experts decide are likely to commit similar outrages in future if left at large.
The final decision would be left up to the court. Confinement would be for a set period (as yet undetermined) during which the offender would undergo treatment.
Although naturally horrified at the recent spate of killings, not all Japanese think the government has found the right answer.
The Federation of Bar Associations quickly issued a warning that "there is a danger the abuse of such confinement could violate the public's human rights." A spokesman said preventive confinement was not an effective crime prevention measure.
He also questioned the criteria on which the court would decide a defendant was likely to commit similar crimes if left at large.
The Society of Psychiatry and Neurology, as well as organizations for mental patients, condemned the proposal as designed to oppress the mentally ill. They said the confinement would be decided on the basis of "prejudice and presuppositions."
Other critics said the measure, while obviously based on the very best of intentions, could be abused if there was a radical change in the political hue of the Japanese government. For example, there is the precedent of the Soviet Union treating political dissidents as mentally ill.
Some compare the proposal to the "thought control" policies of Japan's prewar military-dominated governments.
A government spokesman, however, said he believed the overwhelming majority of the public supported the measure.
"Basic human rights are fully protected by the Constitution, and I don't believe this measure will infringe on them at all."
There is, however, a strong public feeling that confining those known to be prone to violence is not the full answer to the problem.
A frequent comment heard these days is that the random killings are really an explosion of anger at the cold, impersonal nature of modern, Japanese society which is leading to alienation and other psychological problems.
Today the use of stimulant drugs is as high as it was in the dark, hungry days after World War II. The greatest growth in addiction has been among children and housewives.