@clay, to clarify, “normative” does not mean “subjective preference.” It refers to claims about what institutions ought to do or what arrangements are justified. A preference-based account can be one normative theory, but it does not define or exhaust normative theory. Your appeal to unanimous hypothetical preference behind a veil of ignorance is itself a substantive normative argument. Its assumptions and conclusions remain open to examination; they do not make the normative question disappear.
You write that normative theory “cannot float free of what people would actually prefer.” That is true in the limited sense that preferences can and should inform normative judgment. But normative judgment is not wholly determined by existing preferences. People can prefer domination, discrimination, exploitation, or institutions that violate rights. Normative theory asks whether such preferences ought to govern.
Even after preferences are known, one must still decide whose preferences count, under what conditions they count, whether adaptive or malicious preferences count, how rights constrain aggregation, and whether future generations or constituent institutions should have standing.
Moreover, the veil does not mechanically yield your conclusion unless we specify the agents’ information, risk attitudes, conception of political goods, and whether they value only equal individual influence or also protections against persistent territorial domination and the political standing of constituent jurisdictions. Those are themselves normative and institutional questions.
You say that “the preferences here are not in doubt.” That appears central to your argument, but it is precisely what I doubt. Which preferences do you mean, and why should we assume that every person behind the veil would rank the available institutional arrangements in the same way?
The mathematical representation theorem may be valid conditional on its axioms. What does not follow is that those axioms adequately describe actual human preferences, capture all politically relevant values, or uniquely determine institutional design. To support your conclusion, you would need to show why the assumed preference structure, informational conditions, and conception of relevant goods are appropriate here, not merely that the conclusion follows once those assumptions are imposed. Even granting Harsanyi’s result, an additional argument is required to move from equal treatment in a social-welfare representation to the claim that every legitimate political institution must represent individuals directly and only in proportion to population.
The normative question I am raising is whether higher-level offices should remain directly accountable to the statewide population as a whole or instead be constituted partly through the local jurisdictions with which they coordinate. You say that “the remaining question isn’t open; it’s settled.”
Does your position therefore imply that any institution giving constituent political units standing independent of their populations is necessarily normatively indefensible? In particular, do you regard equal state representation in the U.S. Senate as democratically illegitimate in principle? If not, then the question cannot be settled merely by asserting equal per-person weight as the only admissible representational target. If so, that would imply that a central feature of many federated democratic systems—giving constituent units some standing independent of population—is democratically defective in principle.
This returns to my example of an 80–20 coastal–rural division. A persistent territorial minority may be outvoted indefinitely even when its interests are geographically concentrated, structurally distinct, and directly affected by decisions made at the higher level. I do not think your appeal to cardinal voting adequately resolves that problem. Cardinal voting may register the intensity of individual preferences, but it does not by itself guarantee institutional standing or protection for a territorially concentrated minority.
Federated structures address that problem by giving constituent units some independent role in higher-level decision-making. They also create other risks and tradeoffs, including unequal influence, entrenchment, and minority veto. The question is how those competing values should be balanced. It is not obvious, and certainly is not established by Harsanyi’s theorem, that there is one uniquely correct structure of political representation.
Consider two unions containing the same people and the same total population. In one, the local jurisdictions dissolve into a unitary government. In the other, they retain governments, responsibilities, and limited rights of self-rule while delegating specified powers to a common higher authority. Must the higher-level institution have exactly the same representative structure in both cases? If not, then population arithmetic alone does not determine the appropriate unit or structure of representation. The constitutional relationship among the constituent political units also matters.
Taken to its logical extreme, your principle also seems to undermine political boundaries themselves. If equal per-person influence is the uniquely legitimate representational rule, why should only residents of a state or nation participate in decisions affecting that territory? Why should the populations of China and India not collectively exercise more influence over policy in Hawaii than Hawaiians do?
Presumably the answer is that Hawaii belongs to a bounded political community whose members possess some claim to self-government. But that means the relevant constituency cannot be derived from population arithmetic alone. It depends on prior normative judgments about political membership, jurisdiction, sovereignty, self-determination, and the allocation of authority.
So the fundamental question remains: equal influence among whom, over which decisions, and within which political community? Until those questions are answered, equal per-person weighting is not a complete theory of political representation.