Historians have offered a broad spectrum of conflicting interpretations concerning the nature and timing of the decisions for the Final Solution. To outsiders the debate on the decision-making process in general, and both Hitler's role and the timing of decisions in particular, may often seem the arcane equivalent of a medieval scholastic dispute over the number of angels that can stand on the head of a pin. But to participating scholars this debate has remained of central importance because understanding the decision-making process has proved inseparable from understanding both the wider historical context for these decisions and the structure and functioning of the Nazi system. The debate over decision making has quite simply refused to go away precisely because it is indispensable for shedding light on other questions.

This debate over the decision-making process for the Final Solution has now entered a third stage. In the first stage – the intentionalist/functionalist controversy of the late 1970s and early 1980s – the debate encompassed an extraordinarily wide spectrum of interpretation, ranging from those who argued for a basic Hitler decision in the 1920s to those who argued that he made no decision at all. In a second stage, the debate in the late 1980s and early 1990s was conducted on the much narrower front of the single year of 1941. American historian Richard Breitman argued that there was a fundamental decision early in the year as part of the preparation for Operation Barbarossa.