Ray Nagin, who last was heard blaming everyone but himself, is a mayor without a city. The New Orleans mayor, so unprepared for Katrina and so ineffectual afterward, is on a speaking tour in Memphis, Houston, and Atlanta. He is urging, no, pleading, with displaced residents to come back. From the sound of it, most aren’t buying. And why should they? The city was a cesspool of crime, poor schools, and corruption. And that was before the hurricane.