But by the time it made its way to New Orleans, it had lost most of its strength and been downgraded again, to a “tropical storm.” That’s relevant, because a tropical storm should never have broken through New Orleans’s flood defense. Katrina did break through, however, because the levees that protect the city did not hold. Why? We now know that despite repeated warnings about the risk, the Army Corps of Engineers had allowed the levees to fall into a state of disrepair.
