THE CRIMINAL CASE that ended last week with the conviction of two former FBI executives for conspiring to violate the basic rights of American citizens was disturbing in several respects. It was disturbing that the trial had to be conducted at all and that two men, who believed they were doing what was best for their country, had to be convicted of a serious crime. And it was also disturbing to hear once again the evidence of how far this country had moved by 1970 from its original commitment to restraints on government. Yet all of this was essential to ensure that the door that has now been shut on an unseemly recent past is not reopened.

The basic facts in this case were never in serious dispute. W. Mark Felt and Edward S. Miller did not deny that they authorized lower-ranking FBI agents during 1972 and 1973 to secretly search, without warrants, five homes in New York and New Jersey in a hunt for bombing suspects. These were only a few of the surreptitious entries into homes conducted by the FBI in its effort to find or keep tabs on the more violent and vociferous opponents of the war in Vietnam.

Beyond that, however, this case grew murky. Mr. Felt and Mr. Miller asserted that they had been granted legal authority by the director of the FBI to authorize those "black bag jobs" that he, in turn, had been granted that authority of the president. Both the prosecution and the defense assumed the president had that kind of power, an assumption bolstered by the testimony of former president Nixon and three former attorneys general. It was apparently in the jury's perception of how that power filtered down to them that Mr. Felt and Mr. Miller came out as losers. They may or may not remain losers after higher courts review their convictions. The relevant law is complex and its applications to this particular situation far from clear.

Regardless of what happens on appeal, however, this case is a landmark that should deter future policemen from overreaching their legal authority. Mr. Felt and Mr. Miller knew or should have known they were on dangerous ground when they approved housebreakings. The ease with which that approval was granted and the assumptions under which these two men operated made it essential that they be prosecuted. The Department of Justice was wise in refusing to whitewash such a matter, even though it involved some of the nation's best law enforcement officers.

This is just one part of a tawdry chapter in the FBI's history. All of its misdeeds, and there were many, grew from the assumption that is at the heart of this case -- that when national security may be involved, the traditional and constitutional rights of American citizens can be wiped out by executive decree. That lies behind the assertion that the president, any president, can order secret searches of private homes. It also lies behind the approval that was given all too readily to mail covers, wire taps, surveillance and counter propaganda.

That assertion, made not just by former presidents and attorneys general but also by many members of Congress, seems far removed from the language of the Fourth Amendment and the history that inspired its wording. In reviewing the convictions of Mr. Felt and Mr. Miller, the higher courts would do well to examine that claim closely. Is it necessary, in the modern world, to permit any president or any law enforcement officer to exercise power so out of keeping with the original understanding of what personal privacy is? We think it is not.