The Supreme Court's ruling in the New Jersey reapportionment case will have only a negligible effect--other than a substantial nuisance effect--on New Jersey and 16 or so other states. But the decision is dismally fascinating as an illustration of how judicial activism is apt to produce, over time, judicial extremism.

After the 1980 Census, New Jersey's legislature reapportioned the state's 14 (down from 15) congressional districts. The average population of the 14 is 526,059. The new districts differed from that figure by--on average--just 726 persons, or 0.1384 percent. The largest district had 527,472 persons, the smallest 523,798, a difference of 3,674 persons or 0.6984 percent. Close enough? No, say five members of the Supreme Court, that difference violates constitutional values.

A New Jersey group went to court, charging that this plan violates Article I, Section 2, of the U.S. Constitution, the relevant portion of which says only that members of the House of Representatives shall be apportioned among the states "according to their respective numbers." A lower court said the microscopic differences between districts under New Jersey's plan were intolerable. That court said the deviations from absolute numerical equality were not "unavoidable" and were unacceptable, especially in light of the fact that an alternative plan had a maximum population difference between districts of 0.2470 percent less than the plan New Jersey adopted.

Now the U.S. Supreme Court has squinted at its constitutional micrometer and agreed. New Jersey has not approached absolute numerical equality "as nearly as practicable," and therefore has not made a "good faith effort" to satisfy the constitutional standard. Here we have the majority of justices jerking a leash on a state legislature because it allows congressional districts to differ, on average, from perfect equality by 0.1384 percent.

It was not until the 1960s that the Supreme Court plunged into this political thicket and discovered that the Constitution mandates "one man, one vote." That slogan meant that a vote in one district should have the same weight as a vote in another district.

But what would count as the "same weight"--how close would be close enough? In 1964 the court said: "Mathematical exactness or precision is hardly a workable constitutional requirement." But the court has an inclination toward ever finer fine-tuning of society. And now it has found in a minute difference a difference of constitutional dimensions.

Justice Brennan wrote the opinion. He was joined by Marshall, Blackmun, Stevens and--what is a nice lady doing in a crowd like this?--O'Connor.

Justice Byron White, joined in dissent by Burger, Powell and Rehnquist, notes that the Census Bureau estimated the inexactitude in the 1970 Census as 2.3 percent. That is more than three times the maximum variation between districts in the plan the court calls unconstitutional, and more than 16 times the average variation of a district from the "ideal" of perfect equality.

Anyway, the 1980 Census error in New Jersey is unknowable, and certainly is not spread evenly over all districts. Hence, totally equal districts are an impossibility.

In the early 1960s the court was concerned with places such as Georgia, which had not reapportioned for 30 years. In many states, 50 percent differences in populations were common between districts. In 1983 the court is disrupting New Jersey over a maximum difference of 0.6984 percent.

Under the standard requiring an "as nearly as practicable" approach to absolute numerical equality, even Rhode Island, whose two districts have a difference of 0.002 percent (95 persons), can be attacked. As White says, any districting plan can now be attacked "by anyone with a complaint and a calculator."

Of the majority's numerical absolutism, White says: "Such sterile and mechanistic application may bring the principle of 'one man, one vote' into disrepute." But mechanistic jurisprudence is encouraged by reducing constitutional values to slogans like "one man, one vote." Surely it would be sufficient for the court to forbid only apportionment inequalities so severe that they prevent a majority in a state from correcting them.

The court's majority says that any other standard (than "as near as practicable" to absolute equality) would mean "a high degree of arbitrariness." But there is extreme arbitrariness in the majority's equality fetish.

Having rammed constitutional values into the slogan "one man, one vote," the court now desperately embraces a ludicrous absolutism because anything else opens the court to a river of appeals about alternative standards.

This judicial extremism is the Supreme court's defense against the consequences of its own activism. The defense will be unavailing because now, after every Census, the court must sit in judgment on innumerable deviations from perfect equality.