Many liberals find themselves mystified and disgusted by the apparent willingness of many middle- or even low-income voters to put the interests of the powerful ahead of their own. Why do poor southerners vote for cuts to the top tax bracket that don't affect them? Appeals to race and religion are certainly a part of that, but only a part. In reality, there is a more fundamental reason.
One of the central assertions of American conservative philosophy is that the market is moral. Decisions made by the market carry not only the cachet of economic efficiency, but of moral rectitude. Economic success is also moral success. Poverty is not merely a financial or economic failure but a moral failure on the part of the poor person.
That is why conservatives so vehemently oppose income redistribution or social programs for the poor. It is not just self-interest; although it is true that conservatives tend to be wealthier than liberals, the correlation is far from perfect. Rather, conservatives abhor any attempts to mitigate inequality and its effects because they believe equality to be immoral. Inequality is the judgment that the market has levied on an individual's worth. To redistribute income and wealth through taxation and social programs is to interfere with the moral as well as the economic order.
Understanding this helps resolve many of the apparent contradictions in conservative thinking. Conservatives will be outraged over the tiniest waste or inefficiency in social welfare spending but seem oblivious to lavish subsidies for large companies, expensive defense procurements, and other handouts. That is because they have little objection to government spending per se; what bothers them is spending on people "unworthy" of it, namely those in the lower income strata.
Despite their incessant anti-tax rhetoric, conservatives do not oppose a tax increase if the burden falls disproportionately on the "unworthy". Hence their veneration of Ronald Reagan's income tax cuts, while paying little heed to the huge payroll taxes he introduced. Payroll taxes are not unjust to the conservative mind, because they penalize those who are "failures", those whom the market has weighed in the balance and found wanting. Hence also their support for flat taxes, because they shift the burden from the most worthy (the rich) to the less worthy (the middle class).
Liberal appeals to compassion or solidarity only alienate voters of this persuasion. Where we see families in need, they see failures and parasites. Where we feel compassion, they feel contempt. Likewise, attacks on the rich and powerful attempt to appeal to a sense of class consciousness that isn't there. Instead of appealing to solidarity, liberals appear to be endorsing immorality and failure.