The surge in malpractice suits that has so alarmed doctors, investment advisers and even clergy has been targeted at lawyers as well. One of the most contentious issues for state courts in recent years has been whether someone who is not a client can nevertheless sue a lawyer when he or she messes up a case.

Maryland is the most recent state to answer "yes" to that question.

That answer tosses out a century of settled law, because in 1880 the U.S. Supreme Court ruled that in most cases a person who was not a party to the lawyer-client contract had no right to sue for professional malpractice. The only exceptions: outright fraud or collusion, or a clause in the contract giving the third party the right to sue.

California has marked out one route away from this old rule. It is called the "balancing of factors" theory, and tells the judge to look into such things as how close the connection is between what the lawyer is alleged to have done and the harm the plaintiffs claim to have suffered, and whether letting the case go forward would prevent other lawyers from making the same mistakes. In essence, this approach makes it a judgment call for the judge -- the source of a lot of criticism of the theory.

Other states, such as Illinois and Pennsylvania, have followed a different path. Someone who is not the client may sue a lawyer for malpractice, they say, only if the intent of the client was to help the person who is now claiming malpractice. When Maryland first suggested in 1972 that it might accept this reading of the law, the intent was that only a very narrow exception was being appended to the strict no-client-no-plaintiff rule.

But in Flaherty v. Weinberg, decided on May 28, the Maryland Court of Appeals has broadened that exception considerably.

The case involves homeowners who, years after closing, discovered that their property overlapped neighbors' land. They did not have their own lawyer at the closing, but said they relied on the advice of the lawyer for the bank that issued the mortgage on the house.

The Court of Appeals judges noted that not only is a bank lawyer normally acting on behalf of the bank alone, but also that in most financial transactions, the interests of lender and borrower are not at all the same. Nonetheless, they refused to toss out the suit. The fact that the plaintiffs claim that the lawyer's help was meant for them, too, is enough to let the case get to trial, the decision says. There is some solace for lawyer-defendants in such situations: The decision says the judges think it is going to be hard for the plaintiffs to win.