It better helps to understand if one can get free of party affiliation and race, both of which have little to do with the overall picture.
The presidency and for that matter almost all political positions are decided by the media, say and do the right things and receive positive support in the press, run a counter position and risk being ignored or ridiculed.
Case in point would be Obama who was virtually unknown beyond the confines of Cook County one year prior his election to POTUS, the press he received during his campaign was nothing short of spectacular, "Yes We Can" was everywhere, accompanied of course by photos of Obama posed as a modern day Superman, a hero of the people as it were.
Yes indeed, Obama was on the same page as those who so vigorously supported him in the media. Obama was about change alright, just not the change that was truly needed, Obama never called for an audit of the Fed, Obama never called for an end to open borders, Obama never called for the return to Constitutional standards, Obama did call for an end or at least a draw down of the current wars, but sadly he didn't follow through, Obama's inaction led to a downward spiral of the economy, this is his largest failing with the public in my opinion.
Conversely, those who opposed Obama while calling for reforms were virtually ignored in the press and mainstream media, some were even chastised.
The question that begs to be asked is who controls the media and what exactly is their agenda? What governs the decision making process that decides who gets massive, positive press and who doesn't? Some will say that funding plays a major role, while this maybe true with regards towards purchasing air time, it in no way justifies the biased opinions of the network pundits who crow around the clock.
To truly understand what makes or breaks any American politico requires research into who controls the propaganda machine that supports them or shuns them, yes indeed, research into who controls the mainstream media is key in this equation.