As the anniversary of one disaster approaches, Americans are riveted by another. Once again, thousands likely have died. Once again, Americans are asking why. Comparisons between September 11 and Hurricane Katrina are as inevitable as they are unfair. Yet the two share more than an infamous page in the nation\'s history. Together, the worst terrorist attack on U.S. soil and the worst natural disaster in U.S. history are bookends to an era of anxiety. From 19 men with box cutters to families trapped in a dying town without drinkable water, the tragedies have shaken the sense of safety to which Americans are accustomed. Some of the problems can ironically be traced to changes made in response to September 11, said Allen Batteau, a Wayne State University professor of anthropology who heads a federally funded research project on disaster response. Batteau is coordinator of a group going to New Orleans next week to analyze what went wrong. \"Given the bureaucratic nightmare (of the massive Department of Homeland Security), maybe we were expecting too much,\" Batteau said. If September 11 taught Americans how vulnerable we were to our enemies, Katrina taught Americans that we can at times be our worst enemy.