Thanks for the mention, GRC. Let me chime in here for a couple of reasons. I am indeed a longtime radio guy (43 years, at this point, with 30 years as a GM/Mkt Mgr/owner+DOS/GSM) now operating a 5-station cluster out east. Though I haven't worked in SD I know the market well, courtesy of a shitload of relatives living in the city.
Let me also clarify that I am, indeed, a liberal--a progressive liberal, at that. One who believes strongly in the capitalistic free-enterprise system--through which I've made a terrific living--but with enough governmental regulation to protect the nation from the kind of excesses we are now paying for. But that's not the point of this discussion, so let's steer clear of ideology, shall we? Just understand that I'm not neutral.
San Diego--SD County, specifically--voted for Obama last November by a 10-point margin, 54% to 44%, providing strong statistical evidence that the radio market has plenty of population generally agreeing with the ideas supported & espoused by lib-talk radio.
If instead we were trying to determine the viability of an urban format, for instance, and identified a market with 54 percent African-American population, we wouldn't hesitate. If instead we were trying to determine the viability of an easy listening format and identified a market with 54 percent 65+ population, we wouldn't hesitate. Though they're not quite at that (54%) level, those formats work quite well in Mobile, AL (Urban) and Fort Myers-Naples, Florida (EZ). It didn't take hand-wringing research to ID those huge opportunities. And it doesn't take this kind of BS to identify an opportunity for lefty-talk in San Diego, either. (Or DC, Boston, Philly, Baltimore). It's common sense.
Clear Channel--owned & operated by dyed-in-the-wool conservatives--don't run lib-talk in LA & SF in order to promote liberal views. They do it to because there is a huge base of support in those markets, and even on "challenged" signals, they make money. If they had enough moxy to put the format on their big sticks instead of relatively small stations (KTLK & KKGN) the format would kill--because signal still matters. In San Diego they put the format on their worst property, and--like everything else that has been tried on 1360 in recent decades--it didn't light up the sky.
But put it on a competitive facility--AM or FM--and it would do fine in San Diego.
This ain't brain surgery... rocket science... or rocket surgery. Sooner or later, it'll happen. Whether you like it or not.