This system in one hand has maintained categorical rules of classifications as well as simplifications.

The court ruled 6 to 3 that such a categorical rule would make land use planning prohibitively expensive and was, in any event, not required by the Constitution.

Legal intervention, with its categorical rules and sanctions, is said to be incompatible with the adaptive, flexible, social interaction of teaching and learning.

The categorical rule created by the court is unsound and an unwise addition to the law of takings.

And it's hard to lay down categorical rules in that area.

A categorical rule that would outlaw such a choice would wrongfully deprive some women of a legitimate option.

While certain uses of polygraph examinations may be questionable, he said, a categorical rule of exclusion is unjustified.

"The Court has never endorsed the categorical rule the Government advances," Kennedy wrote.

The reasons for rejecting such a categorical rule apply as well to a rule that would require a stay "in all but the most exceptional cases."

Mr. Carroll, the murdered couple's son, said a categorical rule made no sense in the context of the death penalty.