I spoke with my San Diego Republican source about the San Diego Mayor and CA-52 Congressional elections. Initially, the Republican insiders and business interests were neutral about the race. They spoke with Ron Roberts, Carl DeMaio, and Kevin Faulconer, asking each if they'd leave the race if the Republican party decided to get behind a single candidate. Roberts and Faulconer said yes. DeMaio said no.
As they discussed the candidates, the insiders felt that DeMaio was the wrong candidate for mayor. His style can be abrasive and alienating. He's pissed people off. The feeling was that such a style wasn't the best temperament for mayor, especially coming on the heels of Bob Filner.
[Aside: They knew Filner was a jerk, but had no idea he harassed all these women. Most were Democrats. If they had, they would've used it.]
Faulconer is well liked and the type to get people rally behind him. Thus, there was a sigh of relief when DeMaio decided not to run. He didn't feel Faulconer's lack of name ID would hurt him in a low turn-out special, which would be more concentrated with core party bases. I disagree and think he was putting on a good front for Faulconer being unknown.
He felt DeMaio was the only candidate who could win CA-52 and dismissed Kirk Jorgensen as an outsider businessman, pointing out that candidates like him hadn't been able to get votes in the past. DeMaio's style would fit much better with being a congressman and that San Diego Republicans would be firmly behind him.
Republicans have the candidates they want for both offices.