Unfortunately, if you wanted your new "liberal" news network to affect a larger audience you'd need a think-tank to help "propagandize", else you'd be discredited by other motivated interests.
2. There seems to be an inordinate amount of money pouring into campaigns to discredit the sort of thing you might focus on (e.g., climate change[2], which is seen as a liberal idea[3]).
3. Less seriously, it was sub-text'd from Colbert's "Reality has a well-known liberal bias." [4]
_______
[1] http://stateofthemedia.org/2013/cable-a-growing-medium-reach... (2012)
[2] http://www.theguardian.com/environment/2013/feb/14/funding-c...