THE UNITED States is part of an international trio, the other members of which are not usually described as close associates. What the three nations have in common is a significant social problem: this country, the Soviet Union and the Republic of South Africa have the highest prison incarceration rates in the industrialized world. In fact, they may have the highest rates in the world, but the absence of reliable data from developing countries makes that determination purely speculative. It is enough to consider why this country is in the top three for which figures are available.

According to a study released by The Sentencing Project, a nonprofit research and advocacy group, these three countries have led the field for many years, but over the past decade, the United States has risen from third place to first. As of 1989, the imprisonment rate in the Soviet Union is 268 per 100,000 residents. The figure for South Africa is 333 and in the United States it has risen to 426. Two things should be kept in mind about these comparisons. They do not take into account the fact that some inmates who would be counted in the prison population here are listed as mental patients elsewhere, particularly if their offenses are political in nature. In addition, the figures do not reflect the fact that ordinary life in these other two countries is characterized by restrictions on civil liberties and political freedom that affect many more citizens than those in custody. Nevertheless, this country's problem is acute, and high crime rates and government policies are making it worse.

Of course there are long-range solutions offered to reduce crime and the prison population. Gun control, for example, is among them, as are better social services and job training. But two reforms can produce an immediate impact. Harsh mandatory minimum sentences could be abolished. Such things as 10- and 20-year minimums for drug offenders and mandatory life imprisonment for crimes other than murder and other sentences that do not take into account a defendant's personal history or prospects for rehabilitation have contributed substantially to the doubling of this country's jail and prison population in the past decade. Along with this change, far more alternatives to prison should be made available for nonviolent offenders. Electronic monitoring of house arrest works. Intensive parole and probation, with much lower officer-to-prisoner ratios, is expensive but far less costly than prison. This country cannot continue to build prisons at the current rate and pretend that filling them to the rafters will guarantee a better society.