The classical rationale for judicial review of the constitutionality of legislative and executive acts is based on a deterministic assumption about the nature of constitutional legal rules. By the early twentieth century, however, American legal realists persuasively questioned the determinacy of law in general and posited that indeterminate cases were decided by judicial intuitions of fairness. Social science research has discovered that self-identified liberals and conservatives predictably place different relative values on different shared moral intuitions. At the same time, neurological research suggests that humans and primates implement “decisions” before the cognitive parts of the brain are even aware that the subject has made a decision—potentially negating the role of cognitive reason in intuitive human decision making.
Combining these three behavioral insights—that of the realist, the psychologist, and the neurobiologist—seems to undercut the classical justification for judicial review by unelected judges. If intuitive ideology rather than reasoned application of rules controls much judicial decision making, then the Supreme Court has no more authority to issue binding interpretations of the Constitution than those branches of government whose ideological leanings are more directly subject to political controls. Nevertheless, the Supreme Court's structural role as a potential restraint on unconstitutional government action and as the ultimate arbiter of constitutional disputes, together with institutional and political restraints on judicial activism, leaves an essential practical role for judicial review in the U.S. constitutional system.