Ever since I can remember, presidential candidates (even incumbents) have captured the minds of the people by talking about "change" or "reform" or "rebirth" or "a new day" or something of the sort. There's a natural reluctance to detail the specifics of how exactly such "change" would manifest legislatively or in specific policy terms because then, naturally, some people would be alienated as their vision of change differs from the candidate's vision of change. However, everybody tends to always agree that "change" is what is needed. We can all support a candidate that offers change in the abstract.
I'd suggest that this is due to some sort of fundamental unease or existential anxiety in the human experience. Change offers hope, but hope for what really? Some escape from mortality?
Politics of course is so much more about symbolism than wonkish policy stuff or even concrete action. If we were to somehow shut off all media from our lives, most of us would feel very little change in our day to day lives whether or not, for example, the president sends troops to Haiti or whether gays get married or whether partial-birth abortion is banned. These issues may be enormously consequential in our minds to the extent that they take on a metaphorical signirficance in relation to our actual experience. At the core it's pretty insane.