Winner of the Thomas M. Cooley Book Prize, Georgetown Center on the ConstitutionWhy do self-proclaimed constitutional "originalists" so regularly reach decisions with a politically conservative valence? Do "living constitutionalists" claim a license to reach whatever results they prefer, without regard to the Constitution's language and history? In confronting these questions, Richard H. Fallon reframes and ultimately transcends familiar debates about constitutional law, constitutional theory, and judicial legitimacy. Drawing from ideas in legal scholarship, philosophy, and political science, Fallon presents a theory of judicial legitimacy based on an ideal of good faith in constitutional argumentation. Good faith demands that the Justices base their decisions only on legal arguments that they genuinely believe to be valid and are prepared to apply to similar future cases. Originalists are correct about this much. But good faith does not forbid the Justices to refine and adjust their interpretive theories in response to the novel challenges that new cases present. Fallon argues that theories of constitutional interpretation should be works in progress, not rigid formulas laid down in advance of the unforeseeable challenges that life and experience generate. Law and Legitimacy in the Supreme Court offers theories of constitutional law and judicial legitimacy that accept many tenets of legal realism but reject its corrosive cynicism. Fallon's account both illuminates current practice and prescribes urgently needed responses to a legitimacy crisis in which the Supreme Court is increasingly enmeshed.