政府的政治偏好函數反映、體現各競爭團體的不同利益和政治權力。本文在公用
事業產品的消費者，不僅包括家計單位也包括廠商的二類顧客（ 2-class customer ）的架
構下，建立一利益團體競爭的模型，並以政治偏好函數統合公用事業費率訂定中各抗爭團體
的不同利益和政治權力。我們分析政治偏好函數和三種不同型態的訂價方式－利潤極大化、
邊際成本、Ramsey －之間的關係， 分析重點在於此三種不同型態的訂價方式背後所隱示的
政治權力結構。我們的主要發現是，令政治程序執行次佳 Ramsey 訂價法則的公用事業費率
的必要條件在於： 要不維持勞動者和資本家間政治權力邊際上的平衡， 就是內化（
internalize ）勞動者和資本家間的利益衝突。

A government's political preference function embodies political powers
among competing interest groups. This paper constructs a model of competition
among interest groups and employs the political preference function to study a
2-class customer (households vs. private firms) public pricing problem. We
analyse the relationship between the political preference function and three
forms of pricing rule- profit maximization, marginal cost and Ramsey. The focus
of the analysis is on the structure of political power behind these three forms
of pricing rule. Our main finding is: The second-best Ramsey prices will be
enforced in a political process only if either (i) keeping a balanced political
power marginally between laborers and capitalists, or (ii) internalizing the
conflicting interests between laborers and capitalists.