This groundbreaking book analyzes the decisions made by the United States circuit courts over the past half century. These courts have a profound impact on the law—they issue many more decisions in many more areas of law than the Supreme Court. Cross demonstrates that while the courts' judges are influenced by ideology and by the appointing president, legal requirements exercise a much stronger influence on their decisions. He also shows that these courts are independent of the other branches of government and free from undue influence of various parties. The book further introduces new research on the precedent-setting power of decisions.