Source: The StarLedger, 1 Star Ledger Plaza, Newark, NJ 071021200 Pubdate: May 5, 1997 Contact: Mixed signals Before the cops can enter a home to search for illegal substances, they have to knock. So says the U.S. Supreme Court and it's right. The justices also say that if an overzealous cop breaks your leg, you can't sue the government and they're wrong. That's the good news and the bad news about civil liberties that came from the high court this week. In a unanimous ruling, the court refused to exempt police on drug cases from the general requirement that they knock and identify themselves before searching for evidence. The decision may upset some in law enforcement, but it's consistent with constitutional provisions. Citing concern for officers' safety, a Wisconsin Supreme Court ruling allowed a blanket exception to the requirement when drugs are the object of the search warrant. But the Fourth Amendment, barring unreasonable search and seizure, doesn't permit exception based on the priorities of the times, the U.S. Supreme Court said. However, in another ruling, a sharply divided court made it harder to sue local governments over excessive force used by their police officer. The 54 decision might also make it more difficult to sue local governments over other violations of federally protected rights. The court said Bryan County, Okla., was wrongly punished for a 1991 incident in which a deputy threw a woman to the ground with such force that she's needed four operations and will ultimately require total knee replacements. The brute deputy had been hired by his uncle, the sheriff, despite a long record of misdemeanor convictions. Justice Sandra Day O'Connor wrote for the court that although the sheriff made a poor decision, the county wasn't liable for the damaging results. The decision waters down a line of Supreme Court rulings, dating back to 1978, that subject local governments to civil rights lawsuits. It's a step in the wrong direction. The mind of this court is hard to figure. On the one hand it upholds protections to keep law enforcement officers from breaking down your door without knocking, but on the other, it says you can't sue city hall if one of them breaks your legs. Reader Forum letters: 200 words max Speaking Up columns: 500 words max