Mario Cumo tried a leftist show. It failed. Alan Combs has failed to generate anything near the Limbaugh audience.
The interesting fact is that rescent surveys show that of the total audience 17 percent call themselves liberals, 34 percent call themselves conservatives and 49 percent call themselves moderates.
By every definition Liberals delegate to governemnt the task of taking care of their welfare. They have no interest in public affairs because they delegate them to the Democrtatic party.
Republicans reserve for themselves the right to run their own lives. Thus they have an interests in public affairs.
There is no way to draw a huge liberal audience for a public affairs program.