William Saracino has the best mainstream analysis yet of why Simon beat Riordan. It matches up quite closely, of course, with my own analysis.

The Riordan operation resembled a bus carrying no one who knew how to get where it was supposed to go. The campaign hierarchy, filled with partisan Democrats, had no idea how to appeal to Republican primary voters. It is drilled into Democrats from their youths that Republicans, especially those terrible ?right-wingers,? have neither hearts nor minds ? that they are idiots devoid of ?compassion.? So it should be no surprise that those driving the Riordan bus lacked directions for reaching GOP voters? hearts and minds or that, in the end, they came nowhere close to their destination, winning a Republican primary.