One issue that Fiorina does not look at, however, is patriotism. Since 9/11 and especially with the Iraq War, many commentators have suggested that patriotism is an important fault line between the parties. From watching the Republican convention you would certainly get the idea that the Republicans are the party of patriotism and the Democrats are the party of "blame America first."
To get a better sense of this I looked at a patriotism variable in the 1988, 1992, and 2002 National Election Surveys (NES). The question is "How strong is your love of country?" and the responses, ranging from 4 to 1, are extremely strong (4), very strong (3), somewhat strong (2), and not strong at all (1). Below are the average responses by ideology and party identification for each year:
This table shows several things. First, Americans, regardless of ideology or party are highly patriotic. These average scores, about midway between 3 and 4, indicate that the vast majority of Americans have extremely strong or very strong love of country. Furthermore, there are no significant differences in love of country along ideological and partisan lines. Yes, conservatives and Republicans are a bit more patriotic than liberals and Democrats, but the differences are very small. Finally, there is no evidence that these divisions are increasing. In fact, they didn't budge an inch between 1992 and 2002. So much for the patriotism gap.