The mass murder of 20 children and six adults Friday in Newtown, Conn., has provoked yet another round of recrimination, finger pointing and breast-beating. Was the shooter mentally deranged? If there was more gun control, would this have happened? Did violent video games play any role? What we fervently want as we continue to reel from a story whose misery seems to know no bounds is to find a clear cause - a reason why this happened - so that we can fix it.