Under its current lines, the CD gave McCain 51% and Romney 55%. That doesn’t look like a district that’s quickly trending Democrat. There are seven GOP-held CDs in CA that are less Republican than the CA-45 (including Darrell Issa’s CD), and none of the other seven Republicans have retired due to fear of losing (even though several sit in Dem-leaning districts, and Gary Miller’s seat is prett strongly Democrat). I don’t know why Campbell is retiring, but it isn’t because he has adopted a sky-is-falling attitude that makes him think that a district in which Obama only got 43.0% while he was coasting to a 59.3% romp statewide would be hard for him to hold.
Here is a whopper- Gary Miller is thinking of moving into the district to run. That would be office-shopping at its most blatant.