The U.S. Attorney General is forever caught between competing demands: on one side, his political duties as cabinet appointee and adviser to the president; on the other, his quasi-judicial responsibilities as chief law officer of the nation. In theory the two sets of responsibilities coexist peacefully. In reality they often clash.

In Conflicting Loyalties, political scientist Nancy Baker provides the first comprehensive analysis of the history and structure of the office of the U.S. Attorney General, an office that legal scholars have described as "schizophrenic." Her study...