There is certainly media bias against President Obama. And this is very ironic, because conservatives are always rumbling and grumbling about the "Liberal media." In fact, there are more conservative news networks and radio station personalities in the States than there are Liberal--and guess what? They all despise Barack Obama.
While the majority of the media is in favor of President Obama there are certain conservative media networks that are biased against the President, these networks know that the majority of their viewers are displeased with a democratic President so reporting biased news that makes him look bad makes their viewers happy and tune in.
My argument for this would begin with the fact that the media ALWAYS skews the facts at least somewhat. So, already, any argument that there isn't media bias against Obama is on shaky ground. This, combined with the fact that the "republican-esque" news programmers, like FOX, are TRYING to twist the facts, it isn't just happening sub-consciously.
No, there is not a media bias against Obama, because they protect him. Many more people have died in Afghanistan under Obama's watch than Bush's, but Bush was considered a war monger, and Obama is hardly even questioned for leaving troops there. Obamacare and its debacle is not questioned by the media, either.
American journalism offers multiple points of view on
President Obama and every other issue. Fox News is considered right wing, while
the offerings of the New York Times are considered to be somewhat to the left
by many observers. A range of editorial viewpoints guarantees that any news
bias exhibited by one source will be countered by others very quickly.