ng the home as having excess capacity. It does not follow, however, that the government would be justified in forcing the owner to rent the home to another person who wished to occupy it during the winter for only a nominal fee. The rent that normally would be charged would depend upon the number of other possible renters as well as the amount that the owner could obtain by refusing to contract at a particular price. Constitutional Limits on the Pricing of Access to Networks The emergence of platform competition and the shift from rate regulation to access regulation compel a different constitutional analysis of regulation. Because rate regulation simply adjusts the terms under which parties can contract, it represents the type of nonpossessory regulation traditionally subjected to a rather permissive standard of review under the Takings Clause. This standard requires only that the rate fall within a zone of reasonableness. Compelling access to a physical network, in contrast, invariably requires the network owner to permit third parties to locate equipment on its property. As such, access regulations are subject to the more restrictive standards associated with the Court's physical takings jurisprudence. Unlike nonpossessory regulations, in which reductions in the value of property are not necessarily compensable, physical takings necessarily command market-value compensation. Principles of constitutional law thus reinforce the basic economic conclusion that network access should be priced at market levels. A. The Distinction between Physical and Nonpossessory Takings 1. The Emergence of the Nonpossessory Takings Doctrine Initially, the Takings Clause was believed to protect only against direct government appropriations of private property or invasions that effectively divested the owner of possession as though the government formally condemned the property. Gov- ernment actions that merely reduced property value did not qualify as takings. 1 The Court subsequently recognized two types of takings that can arise 