Regarding the election, how much of a factor is media bias in terms of influencing voters?

The difference between news organizations and opinion or propaganda stations have blurred in recent decades, but especially in this election cycle.  The Trump campaign has now undergone a third makeover (since April), taking on Stephen Bannon of Breitbart as his new attack bulldog.  They have come out with fake medical records on Hillary Clinton purporting she has a “grave health crisis and severe neurological impairments”.  These lies are meant to influence voters away from supporting her, as were the ad nauseam commentaries by pundits about a LEGAL email server Hillary had when Secretary of State, and innumerable months of coverage regarding  bogus investigations into the embassy attack on Benghazi, accusing Hillary of being “personally responsible” for the deaths of four men at the embassy, (which Congress found to be under-secured, after they denied requests for more monies for beefing up embassy security!)  The Secretary of State does not command defense operations!  The news anchors know better, even though the “negative innuendo” seeps in from other sources.  The blatant lies, myths perpetuated and dirty tricks receiving constant coverage have blurred the lines in the minds of viewers.  As it concerns Hillary, it is misinformation overload!    As for Trump, he is like an obsessive dog, digging himself in a deep hole and cannot stop!