https://en.wikipedia.org/wiki/Functionalism%E2%80%93intentio...

> The debate on the origins of the Holocaust centres on essentially two questions:

> Was there a master plan on the part of Adolf Hitler to launch the Holocaust? Intentionalists argue there was such a plan, while functionalists argue there was not.

> Did the initiative for the Holocaust come from above with orders from Adolf Hitler or from below within the ranks of the German bureaucracy? Although neither side disputes the reality of the Holocaust, nor is there serious dispute over the premise that Hitler (as Führer) was personally responsible for encouraging the anti-Semitism that allowed the Holocaust to take place, intentionalists argue the initiative came from above, while functionalists contend it came from lower ranks within the bureaucracy.

It seems the general consensus is "a bit of both":

> [...] Given the fact that scholars have written so much in relation to Nazi Germany, Richard Bessel asserts that, "The result is a much better informed, much more detailed and more nuanced picture of the Nazi regime, and most serious historians of the Nazi regime now are to some extent both 'intentionalists' and 'functionalists'—insofar as those terms still can be used at all."[20]