A bad old political joke (mainly told by Jews) is that American Jews live like Episcopalians but vote like Puerto Ricans.
The update is by Stephen Ansolabehere, Jonathan Rodden and James M. Snyder, Jr., who's "Purple America" appears in the latest Journal of Economic Perspective (reg. req. Spring, 2006).
They conclude: "Ultimately, individuals' beliefs about what is right or fair economic policy for the nation are difficult to explain. They are only related weakly to one common indicator of self-interest -- income -- and they are nearly uncorrelated with cultural issues. Since these policy preferences appear to be one of the main forces driving voting behavior, however, explaining them is clearly a key question in American political economy."