Presidential elections turn first and foremost on candidates, but they also hinge on the mood of the electorate. Are voters happy when they head to the polls? Angry? Scared? Are they satisfied with the economy and with the direction of the country? When Barack Obama easily defeated John McCain in 2008 to become the nation's first black president, he was not only the candidate who offered the chance for a historic first; he was also the younger, more dynamic, more charismatic of the two.