Responding to complaints that the prosecutions of two presidential friends were sent to judges appointed by President Clinton, a federal appeals court judge said the way some cases are assigned is open to abuse.

Appeals court Judge Stephen Williams made the comment in dismissing a complaint against nine Democratic judges, including Norma Holloway Johnson, chief judge of the District Court here. In a Nov. 17 decision released yesterday, the appeals court threw out as "frivolous" the complaint brought by Judicial Watch, a conservative group.

Johnson has maintained that political considerations had nothing to do with her bypassing the system of assigning cases randomly by computer when she named the judges who would hear the cases against longtime Clinton friend Webster L. Hubbell and former Little Rock restaurateur and Democratic fund-raiser Yah Lin "Charlie" Trie.

Johnson was in meetings and unavailable for a comment yesterday, said her administrative aide, Joe Alexander.

Williams found no evidence of misconduct but criticized the court rule because it "makes possible both actual and perceived abuses."

Only four of the 13 judges in the District Court are Republicans, so it "is neither damning nor surprising" that Johnson assigned the cases to Clinton appointees, Williams wrote. But he added: "I do not intend to imply that the local rule allowing nonrandom assignment of cases is beyond criticism."