The Mainstream Media, also known as the MSM, is the aggregate term for the traditional news sources of American politics.
Examples include CNN, ABC, and FOX. Although the media is often accused of having a liberal bias, it would be more accurate to say that it has a sensationalistic bias.
This is evident in the way the media has given preferential treatment to John McCain and Hillary Clinton at certain periods of time in order to create a narrative of a close and competitive race.