> One must of course speak in generalities but it seems obvious they have at least one goal in common: to remain wealthy & empowered, come what may. Which of course has implications for which public policies succeed and which fail.

The self-interested voter hypothesis has been examined empirically quite a bit and the lack of evidence for it is pretty surprising. To avoid the risk of cherry-picking, let's look at a few papers that support your assertion, and look at how they describe the literature.

In the first paper, "Caught in the Draft: Vietnam Draft Lottery Status and Political Attitudes,"[1] the authors found that eligibility for the Vietnam draft had a significant and quite strong effect on political opinions. Here's how the authors describe previous research on self-interest and public opinion:

> Self-interest effects have been notoriously elusive in public opinion research. [...] "Longino (1973) found more negative attitudes toward the war among those with low lottery numbers, but not to a statistically significant extent (reaffirmed by Bergen’s (2009) reanalysis), while Aspler (1972) found more disapproval of the draft. Yet,civilian attitudes toward (or related to) the war in Vietnam have been shown to be at best weakly related to self-interest indicators whether one has a family member or friend serving in Vietnam (Lau, Brown,and Sears 1978, Mueller 1973). Indeed, Lau, Brown, and Sears (1978) find “no evidence that the self-interested had distinctly self-serving attitudes toward the war” (p.479).

Here's another paper, titled "A Reconsideration of Self-Interest in American Public Opinion,"[2] let's quote their introduction:

> A fairly extensive body of research has investigated the weight that self-interested concerns carry in defining the opinions that citizens come to adopt (e.g. Bobo and Kluegel 1993; Feldman 1982; Green and Gerkin 1989; Kinder and Kiewiet 1981; Lau, Brown, and Sears 1978; Sears, Hensler, and Speer 1979; Sears, Lau, Tyler, and Allen 1980; Sears and Citrin 1982; Sears, Huddy, and Shaffer 1986; Tyler 1990). Over and over in these studies the same conclusion emerges: the evidence for self-interest effects is, in most cases, weak at best. In an early review of this literature Lau and his colleagues concluded that "[i]n all these cases, self-interest, defined in terms of real or potential impact of a policy issue upon the individual's personal life, had only minor effects on policy attitudes and upon behavior connected with them" (Lau, Brown, and Sears 1978, 479). More recent reviews have reached similar judgments (e.g. Citrin and Green 1990; Kinder and Sears 1983; Sears and Funk 1990).

They buck the trend of looking at material self-interest to look instead at subjective self-interest--"asking respondents to indicate whether the policy would have (national health care, school funding) or has had (affirmative action) either positive or negative consequences for themselves personally," and find a strong effect on opinion. (Given what we know about the human tendency to deny all costs of a favored policy, or deny all benefits of an unfavored policy, I fear that this is a pretty thorny definition of self-interest.)

A third paper, "Self-Interest and Public Opinion Towards Smoking Restrictions and Cigarette Taxes,"[3] finds that nonsmokers are "far more enthusiastic about tightening smoking restrictions and increasing cigarette taxes than smokers, particularly heavy smokers." Unfortunately I can't find an ungated version, but here's their abstract:

> A burgeoning literature suggests that self-interest has little influence on policy preferences. In sharp contrast are the findings discussed in this paper. [...] We conclude by discussing several explanations for the apparent discrepancy between these results and the pattern of null findings characteristic of the self-interest literature.

So, three papers, all of which support your claim that political opinions are self-interested. To describe the existing evidence, they use words like "notoriously elusive," "weak at best," and "pattern of null findings." You can look through the literature yourself but what "seems obvious" has been studied quite a bit, and the evidence that our intuition is correct has been surprisingly sparse.

[1] http://www.columbia.edu/~rse14/vietnam_rev_Feb2010.pdf

[2] http://www.electionstudies.org/resources/papers/documents/ne...

[3] http://poq.oxfordjournals.org/content/53/1/1.short