We argue that the Supreme Court’s expressed and latent demand for information on the availability and implications of legal policy alternatives will affect the supply of information provided to the Court by organized interests. An analysis of the annual growth in amicus filings at the Court during the 1949 through 2008 terms largely supports our specific hypotheses. The rate at which the Court cites amicus briefs and shifts in the Court’s ideological location or agenda exert a positive effect on the growth of amicus filings, while the evidence for the effect of dissensus is mixed. We further show that the supply of briefs does not affect the Court’s expressed or latent demand for information.