One thing that always has to be kept in mind regarding how people evaluate any candidate's performance is this:

The opinion they already have about the candidate profoundly influences their evaluation of the candidate's behaviour.

If they already like someone, then they will put the best interpretation on what he or she says and does. If they don't like someone, they will put the worst interpretation on what he or she says and does.

I see exactly the same problem cropping up all the time on this forum, as regards its membership and the way they relate to one another when they have disagreements about anything. ;-)

So it tends to become very subjective. Those who love Obama already, for instance, will usually think he did a wonderful job in a debate, say, while those who hate Hillary already will sneer at everything she says, no matter what it is.

And vice versa. It cuts both ways.

It's pretty rare to find people who are genuinely impartial and fair in their judgements of politicians...because they usually have a well-used axe to grind.

And that is why those on opposing sides often simply cannot comprehend what in the hell the other people are going ON about! ;-)   (I can't help but think of myself and DougR, for instance, when I say that...)

The mistake they then often make is to assume that the people on the other side of the argument are very stupid...not to mention assuming that those other people believe all sorts of utter nonsense..."After all he MUST believe the utter nonsense I imagine that he does...or why would he be disagreeing with ME! He probably is a communist (alt:fascist), a racist, a secret child molester, a religious fanatic (alt: atheist nutcase), mentally unstable, possibly criminal, a male chauvinist (alt: a man hating shrew) and a complete total loser in every respect possible. An utter tosser, in fact. Someone who does not even deserve to live!"

And right from the getgo the conversation goes straight down the toilet....due to these various extremely subjective assumptions...most of which are facile and quite incorrect.   People's chauvinism toward one another is really a sad thing to witness.

I shall name no names. ;-) (having already mentioned myself and DougR in passing, just for the purpose of illustration, but actually I think DougR is a gentleman and a good guy, despite our differing political views)