The facts are these: On May 4, 1970, Kent State University students rallied to protest President Nixon's decision to expand the Vietnam conflict into Cambodia. Poorly trained Ohio National Guard troops were called to the campus, where, after some mild skirmishing with the students, they fired without warning, killing four and wounding nine. Only one of the casualties had been harassing the Guard; another had been on her way to class when she was shot and killed. The revulsion of those who thought the war wrong crystallized around a photo, widely disseminated then and often reproduced even now, of a dying youngster and the teenaged girl who knelt over him screaming.