MSNBC leans left, but not NEARLY as far as Fox leans right. all of their 'stars' do not hesitate to call out democrats when they fuck up. chris matthews has ripped into Obama many times when he thinks he screws up, and Olbermann has put obama on his daily 'worst person in the world' list before when hes messed up.
Fox however is all republican all the time, no matter what. they appeal to the uneducated man and deal in absolutes and backwards tradition rather than logic and reason.