The Minnesota Supreme Court, in a unanimous decision, ruled today that police may not search lawyers' offices unless they are suspected of crimes or are thought likely to destroy documents bearing on criminal proceedings.

The ruling, a clear victory for American defense lawyers, has stirred interest because it seemed to run counter to the U.S. Supreme Court's search-warrant decision last year in the Stanford Daily case, which left courts considerable latitude in issuing warrants for surprise searches of the offices of journalists and lawyers.

Justice Rosalie Wahl, speaking for the nine-member court, said warrants authorizing searches of attorneys' offices were unreasonable and invalid because they violated the common law attorney-client privilege and the constitutionally protected rights of criminal defendants to counsel. She said:

"The indispensable relationship of trust between client and attorney and the adequate functioning of our adversary system of justice can only be ensured when the client can completely disclose all the facts -- favorable and unfavorable -- without the fear that attorney's files will be seized by police officers pursuant to a search warrant.

"Though this may seem as limiting the ability of the police to obtain information in the early stages of an investigation, we find this measure necessary to protect the overriding interest of our society in preserving the attorney-client privilege, client confidentiality, the work product [of lawyers] doctrine, and the constitutional right to counsel."

In her opinion, Wahl said that the Minnesota Supreme Court wasn't bound by the Stanford case because states have the right to give their citizens greater protection than the safeguards found in the federal Constitution. The case decided today involved a police warrant issued in July 1978 for a search of the offices of David O'Connor, a St. Paul lawyer who was representing the city's fire chief, then the target of an investigation into alleged hidden bar ownerships. The fire chief denied wrongdoing and was never charged.

A lower court trial judge had ruled that the police had the power to seize all of O'Connor's records concerning a certain bar, with the understanding the he'd be obliged to give the police only those documents not protected by the attorney-client privilege.

But the arrangement didn't satisfy the Supreme Court, which said that if the lawyer had not been present when the police arrived (as he happened to have been) the police should have been free to rifle his files until they found what they were looking for.