Relying on polling information and qualitative assessments of popular rhetoric, I would argue that most Americans subscribe to basically the same ideas about economic justice. Even though liberals and conservatives might offer much different policy preferences, the normative ideas that they use to justify those policy preferences converge on two basic principles: just deserts and equal opportunity.
Under the just deserts view, economic justice requires that individuals be compensated in accordance to how hard they work, how much they work, and how valuable their work is. That is, individuals are owed the product of their labor. Generally, I represent this as a conservative ideology, and I think — speaking in broader political theory terms — that it is. But American conservatives and liberals both seem to accept and appeal to just deserts in their thinking about economic issues.
On the conservative side, the just deserts framework is used to argue that high-earners should not be taxed more and that taxes in general are a form of theft. The argument is straightforward. People are owed the product of their labor, and taxes take some of that product away from them. Therefore, people are not getting what they are owed, and we have an economic injustice.
On the liberal side, the just deserts framework is used to undermine the idea that market outcomes actually give each person what they are owed. The recent “you didn’t build that controversy” is a classic example of the liberal application of just deserts. Obama pointed out that any given business outcome has a huge number of inputs, including government investment inputs in the form of roads, security, and so on. So, any given business success is not purely the product of the business owner’s labor, and so he or she is not completely entitled to the gains of it.
The liberal-conservative disagreement here is not about the philosophy, but about the application of it to the present reality. Both sides seem to accept the idea that individuals are owed the product of their labor; they just disagree about what that looks like. Conservatives think all of one’s immediate product comes from one’s labor (or ingenuity or investment or whatever). Liberals think one’s immediate product has a huge number of other inputs (e.g. government investment), which means it is not purely the product of one’s labor.
For both sides, just deserts is not enough: the deserts must have come about within a system of equal opportunity. That is, all individuals must have had an equal chance to capture high-productivity positions within society. If the system is skewed in favor of certain populations — for example children of the affluent — then that undermines the justness of the end distribution.
Conservatives certainly emphasize equal opportunity a huge amount. During the big Occupy swell last fall, Republicans spent a great deal of time beating the drum of equal opportunity and social mobility. One of the very standard distinctions conservatives raise is between equality of opportunity and equality of outcome, emphasizing that the former is what our society promises. Conservatives seem to believe that the current economy is one which provides equal opportunity and that therefore nothing needs to be done on that front.
Liberals argue that our society is not one which provides equal opportunity. Depending on the liberal, points about race, class, gender, sexuality, disability, and so on are usually raised. Huge data sets indicate that social mobility in the United States is low, and stories about rich people gaming the system for their kids are often provided. On the liberal application, because justice requires equal opportunity, and our society does not feature said equal opportunity, it is not fully just. Therefore policy responses are required both to improve equal opportunity and to ameliorate some of the harm visited upon the victims of the current state of unequal opportunity.
Importantly, liberals and conservatives both seem to regard equal opportunity as fundamentally necessary. When liberals make the empirical claim that equal opportunity does not exist, conservatives do not react by saying equal opportunity does not matter. No, they react by saying equal opportunity does exist, and that the liberal is just factually wrong. So as with just deserts, conservatives and liberals seem to have an ideological agreement about justice requiring equal opportunity; they simply disagree about its application.