When Chief Justice John G. Roberts Jr. reached his fifth anniversary on the U.S. Supreme Court in late September, observers took note of the court's rightward shift during his tenure in a number of areas, including corporate spending on federal elections and the ways school districts may consider race in assigning students. But at least one conservative constituency largely is still waiting for its day in the high court. Over the past two years alone, self-described religious-liberty groups on the right have asked the justices to hear appeals in some half-dozen cases involving religious expression in the public schools. In each case, the Supreme Court has refused. The cases recently denied review have involved such subjects as religious music at public school holiday performances, students' distribution of religious-themed items to their classmates, Christian-themed responses to classroom assignments, and religious messages in speeches at graduation ceremonies. What may be disappointing to conservative religious groups is not necessarily so to school administrators and their advocates, who in many cases were on the winning side of the cases turned down by the high court. Some conservative advocates had hoped to see more movement on a perennial source of conflict in public school settings.