For many years, debates over telecommunications network policy were marked by a relative lack of partisan and ideological conflict. In the last decade, this has changed markedly. Today, debates over a whole set of issues, including broadband competition, net neutrality, copyright, privacy, and others, have become more contentious. These disagreements don't stem just from politics, in the sense of conflicts between interests. They also reflect differences over doctrine--differences in deeply held views about appropriate kinds of network policy. Based on these views, different people stress different goals and values and work under different assumptions about how networks and economies work. While many network policy issues have an engineering basis, with disagreements revolving around technical matters, much of network policy is based in economics. And despite what many economists claim, economic approaches to the Internet differ substantially. These approaches reflect differences of economic doctrine among economists, policy makers and others. This paper postulates and describes four competing economic doctrines: conservative neoclassical, liberal neoclassical, neo-Keynesian, and innovation economics. It explains how each doctrine leads to different views of appropriate network policy and explores the influence of doctrine on four controversial network policy issues: broadband competition, net neutrality, copyright, and privacy. (Contains 89 endnotes.)