LAST WEDNESDAY morning, the Supreme Court approved the action of police officers in breaking into an office and hiding a listening device so they could find out what was going on there. That same day, the chief justice ordered an investigation into how a television reporter had found out what was going on inside the court. The two events are unrelated except for this: They reveal how deeply the justices feel about their own privacy and how casually a majority of them regard the privacy of others.

This was not always so. The court once protected the privacy of others as vigorously as it protects its own. Almost every one of its members was appalled 30 years ago when police broke into a house, planted a bug in a bedroom and listened to the conversations of the occupants for a month. Words like "revolting" and "offensive" were used to describe what the police had done.

But no more. Such invasions of privacy have now been officially sanctioned as long as the police have the permission of a judge to listen in. The judge doesn't need to approve, or even be told about, the break-in. That-a crime in any other situation-is standard operating procedure once an eavesdropping warrant is approved.

This incredible situation is the result of the court's steady weakening of the right to privacy in recent years and its willingness to believe it is doing what Congress wants done. In this case, the court said, Congress had approved official break-ins when it passed legislation authorizing judges to issue wiretapping and eavesdropping warrants. But the evidence Congress intended to do that is exceedingly thin. The law does not mention break-ins and its legislative history hardly does. Unofficial history, on the other hand, clearly indicates that proponents of such break-ins skillfully avoided the subject out of fear Congress would reject the idea and in hopes the court would do what it has now done.

Why the court so denigrates the right to privacy is not clear. Perhaps in its anxiety to make the job of the police easier, the majority has forgotten the idea of the sanctity of a citizen's home. Perhaps the majority trust judges so fully it believes they will autorize intrusions only into the homes of criminals who, in its view, are less worth protecting that the rest of us. Perhaps the privacy of the justices themselves has been so zealously protected that they no longer understand the demoralizing effect of having privacy stripped away.

On this last point, the related event of the week-the breaching of the court's own secrecy-is a useful and even happy coincidence. Somebody should tell the justices that their dismay over this minor breach of their privacy is as nothing compared with the distress of a citizen, law-abiding or not, who learns his house has been surreptitiously entered and the living room, or bedroom, bugged so police can "legally" listen to whatever may go on there.