SEATTLE — As he began Mass at St. James Cathedral in Seattle Feb. 9, Archbishop Paul D. Etienne greeted 52 high school students standing in the pews saying, “In a special way, we welcome our high school seniors from across the archdiocese who came here for a day of service.” The students, who are senior leaders at their schools often serving in student government or involved with campus ministry, came from 12 of the Catholic high schools in the archdiocese that have senior classes.