BALTIMORE, DEC. 3 -- The American Civil Liberties Union asked a federal court today to ban traditional prayers scheduled for the University of Maryland's midyear graduation ceremony Dec. 22, contending they violate the constitutional separation of church and state.

In what attorneys believe to be one of few prayer challenges in the country at the university level, the ACLU maintained that invocations and benedictions at Maryland, typically recited by ordained clergy, amount to "state-sponsored delivery of prayers" and thus should not be permitted at public tax-supported institutions such as the university.

The ACLU, in its lawsuit filed in U.S. District Court here, asked that a judge issue an order barring the prayers before the Dec. 22 ceremonies.

James J. Mingle, an assistant attorney general representing the university, said, "We believe the {graduation} program, including short segments of prayer, is constitutional under applicable Supreme Court rulings."

He said that while the courts have drawn strict lines against prayer in primary and secondary public schools because of compulsory attendance and the "impressionability" of children at those grade levels, there is a more relaxed standard at the university level.

Also, the university's human relations office said in negotiations with the ACLU before the suit was filed that prayer and related activity would be unconstitutional only if "entirely motivated by a purpose to advance religion," which is not the case in graduation ceremonies.

The ACLU suit was filed on behalf of university student Matthew J. Barry, 23, of Rockville, a psychology major expecting to graduate Dec. 22, and Americans for Religious Liberty, a Silver Spring-based group dedicated to separation of church and state.

"Barry does not share the beliefs expressed in these {graduation} prayers," the suit says. "He is hurt, offended, excluded and made to feel that he is a second-class citizen by being required to participate in such religious observances as a condition of attending his own graduation."

Barry, who says he is an atheist, has told university officials that when he attended an honors convocation in April at which prayers also were recited, "I felt I was being tacitly told by the University of Maryland . . . that theism was the correct belief and that I therefore was holding an 'incorrect' belief."

The lawsuit, filed by ACLU attorneys Arthur Spitzer, Elizabeth Symonds and Susan Goering, said that negotiations with university Chancellor John B. Slaughter and other officials to remove prayer elements from the graduation failed, and the suit thus became necessary.

Unless the university is ordered to eliminate the prayers, the suit said, Barry "will be forced to choose between having to participate in a ceremony including prayers that he finds offensive and exclusionary, and absenting himself from his own graduation ceremony."

If he misses the ceremony, the suit said, "he and his parents and his friends will lose this once-in-a-lifetime opportunity and will be denied the earned satisfaction and the future memories it would bring."