le to identify three factors with particular significance. Specifically, the Court focused on (1) "the economic impact of the regulation" on the property owner, (2) "the extent to which the regulation has interfered with distinct investment-backed expectations," and (3) "the character of the governmental action." The Court immediately thereafter emphasized that "[a] 'taking' may more readily be found when the interference with property can be characterized as a physical invasion by government than when interference arises from some public program adjusting the benefits and burdens of economic life to promote the common good" (438 U.S. 104, 124 (1978)). What is perhaps most striking about Penn Central is the suggestion that phys- ical and regulatory takings might be governed by the same analysis. The Court's observation that a taking may "more readily" be found when the regulation effects a physical invasion arguably implies that a physical invasion of property is not by itself a taking. Instead, it is simply one consideration that can be overcome by countervailing considerations. The Court seemed to confirm this conclusion in PruneYard Shopping Center V. Robins, in which the Court upheld a California decision requiring that the owner of a shopping center permit a group of high school students to engage in political speech on his premises. In holding that this requirement did not violate the Takings Clause, the Court stated that the students' physical invasion of the shopping center "cannot be viewed as determinative" (447 U.S. 74, 84 (1980)). Many noted scholars have downplayed the importance of this language and argued that PruneYard can be explained largely on First Amendment grounds (see, e.g., Tribe 1988). Nevertheless, a number of lower courts following PruneYard held that the Penn Central factors govern takings that effect physical invasions as well as nonpossessory restrictions on the use of property.7 The Supreme Court soon removed any remaining doubts about the issue. In the first of two leading cases on