Federal and state officials have a lot to answer for in the wake of the Oroville Dam fiasco. They decided in 2005 to ignore warnings that the massive earthen spillway adjacent to the dam itself could erode during heavy winter rains — which it has done — and cause a calamity, which it very nearly did this week and could yet do by the end of this winter. No less to blame are the water agencies, including the powerful Metropolitan Water District of Southern California, which argued that paying for the upgrades a decade ago was unnecessary.