Partisans will vote for their party, unless massive dealignment is observable. Dealignment basically means that the hard and soft issues have changed for the electorate and so the Responsible Party Model shows little congruence with the population. This should cause more people to declare that they are independents, or even switch parties for a while.
Independents will vote for the candidate who best represents their interests, or how they perceive the interests of the country, regardless of Party ID. Independents, prima facie, are not aligned with one of the major parties because each party only speaks well to the voter in part, and, the other party also speaks well to the voter in part. Therefore, independents must, either internally or perhaps via Franklin’s method of denoting the pros and cons of each and then realizing which side has more pros (or less cons), decide at the last minute. Independents must decide at the last minute because there truly is not clear choice (which may be early where early voting is available); and campaigns form strategies to win over independents.
Campaigns to win independents may help exacerbate dealignment. For example, you could research Romney’s primary campaign speeches speaking to the “middle” of the Republican spectrum to Romney’s right; and, in order to win independents, we should expect Romey’s general election campaign speeches to “change” to Romney’s left. Flip-flopping may be verifiable and made into campaign commercials by the opposing campaign, and the degree of it, and this may cause in increase of cynicism and negative advertising, which might increase dealignment too. Perhaps this is why we see Obama over and over again saying that he is consistent–because he is the incumbent and can do so.
Independents may be able to tell you that they voted for Democrats in 2008 and then for Republicans in 2010, and we may even find out which issues were salient in their vote choice (surveys). Therefore, in the 2012 election, polls may accurately reveal most of the independent movement in the 2012 election–if it were held today. And even though this research may be useful in predicting the presidential election correctly, it is only one small step in understanding congruence between the representatives in government and the will of the median voters (please measure sophisticated and gut voters separately for patterns).
Independents may be able to explain much movement in American politics, leaving Party ID in their wake, and sincerely choosing America’s future course.