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－利潤極大化丶邊際成本丶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隠示的政治權力結構。我們的主要發視是，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.