Political scientists draw a distinction between retrospective and prospective voting. Retrospective voting occurs when an electorate decides whether or not to re-elect an incumbent based on how things have improved (or not) over the incumbent’s previous term. This is nearly always based on the state of the economy. Prospective voting usually occurs when there are two non-incumbents in the race. When there is no incumbent, decisions are affected by candidate platforms and characteristics to a larger degree than when there is an incumbent in the race.
Because there was no incumbent in the 2008 election, we might predict that the outcome may have been more affected by prospective than retrospective voting. An article released today in Political Research Quarterly argues, however, that there were two stages to the 2008 campaign:
The findings show that there were two distinct phases of the fall campaign, that retrospective voting was nonexistent prior to the collapse of Lehman Brothers but was strong following the collapse. In effect, the collapse of Lehman Brothers turned the election into a referendum election.
In other words, this article suggests that the collapse of Lehman Brothers in September 2008 converted McCain into a virtual incumbent in the eyes of the electorate. McCain was associated with President Bush and the resulting retrospective voting decisions, which strongly contributed to his eventual defeat.