If you have any doubt about what Democrats think of their keynote speaker tonight, San Antonio mayor Julian Castro, take a gander at this cover image from the San Antonio Current, one of the alternative weeklies out there: Beside the C in the style of the Obama logo, in case you can’t read the small print at the bottom, it says, “CASTRO FOR (insert here)”.When convention organizers announced Castro would be their keynote speaker, I took a look at his record . . . and found little to cheer about in his three years as mayor: When Democrats announced that...