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I. Introduction
Most judicial scholars would agree with Judge Posner’s (1996, 313) statement that “[i]t is
only when the springs of authoritative guidance run dry that judges enter the area of legitimate
judicial discretion.” But our understanding of what Judge Posner calls “the open area” is rather
fuzzy when it comes to judges on the lower courts. Because the Supreme Court is the
authoritative guide to the meaning of the Constitution and federal law, the “open area” for
Supreme Court justices can be described in terms similar to those that modern cosmology uses to
describe the Universe, finite but unbounded. The judges on the U.S. court of appeals, on the
other hand, have policy-making discretion in a much narrower compass, to great extent
“hemmed in” by authoritative Supreme Court guidance. When the Court’s mandate is clear, the
judges of the lower federal courts do not possess legitimate policy-making discretion. But when
the Court’s mandate is ambiguous, those judges enjoy at least some policy-making discretion.
The first goal of this paper is to improve our understanding of the substantive context of
judicial decision-making by examining the nature of legal ambiguity on the federal courts of
appeals. In doing so, it differs from most studies of judicial policymaking by delving deeply into
the substantive nature of the issues presented by the cases. This paper attempts to view cases in
the terms that the judges deciding them would view them. What questions must they address as
they rule in a given case of legal ambiguity? What impact will any choice of a rule among the
potential alternatives have on both the content of legal policy and the functioning of the legal
system? Because ambiguity or indeterminacy is content-specific and context-dependent, I focus
on one policy area, federal drug sentencing policy in the wake of Apprendi v. New Jersey (2000),
a major Supreme Court precedent that disrupted existing procedures and created a great deal of
“open space” for circuit judge policy-making.
Convention