One of the smaller part actresses actually was working at MSNBC when Sorkin was doing his reaserch. He talked her into leaving her job there and taking the job on Newsroom as an actress and writing consultant.
Rumor is that Sorkin brought in several republican speech writers/bloggers/political consultants into the writing room to better balance out the republican/conservative characters which many in the audiance after season one felt weren't portrayed correctly and were coming off as "too democrat/liberal".
Not all who wander, are lost.
I have become death, destroyer of worlds.