The influential twentieth-century German journalist and historian Sebastian Haffner once referred to Adolf Hitler's declaration of war against the United States on December 11, 1941, as the “most mysterious” decision Hitler made during World War II (Von Bismarck zu Hitler [1987], 293). Haffner was not the only scholar perplexed by this decision, as Klaus Schmider illustrates in his illuminating new study about this fateful step. To this day, generations of historians and pundits have expressed their bewilderment about the move that would ultimately doom Germany's entire war effort.

They have offered plenty of explanations, of course, for why Hitler acted as he did. These explanations include the idea that he was driven by a kind of suicidal impulse devoid of any rationality; the claim that, because of his skewed worldview, he gravely underestimated American military power; as well as the assertion that it was a strategic decision based on the realization that American resources and especially the U.S. Navy could only be kept in check if they were forced to divide the power of their military between Japan and Germany. Schmider's work rejects all these explanations. Instead, he offers a novel one, arguing that Hitler's decision-making process was largely “driven by a rational weighing of pros and cons” (9) in the early weeks of December 1941 and was “determined solely by military estimates, rather than ideological paradigms” (549).

Dismissing the role ideology played in one of Hitler's most momentous decisions is a bold move. But Schmider backs up his argument with a plethora of evidence. He starts off by demonstrating that the popular notion that Hitler simply underestimated the United States because of his racist and antisemitic views does not hold—a point recently made by an increasing number of scholars, especially since the publication of Adam Tooze's Wages of Destruction (2006) which emphasizes the German dictator's keen cognizance of America's overwhelming industrial might and the danger this potentially posed for Germany. Schmider then addresses the question of Hitler's physical and mental health at the time he declared war on the United States, demonstrating that he was not yet aware of his serious health issues. This made it highly unlikely that any fears he was personally running out of time played a role in his decision to take on the American giant.

The following chapters provide an in-depth overview of the state of diplomacy between Germany and the United States, as well as between Germany and Japan, before 1941. It is here that Schmider develops his core arguments in painstaking detail, providing us with what, at times, feels almost like an hour-to-hour reconstruction of the events as they played out. Such details are important, it turns out, because they played a decisive role in shaping Hitler's grand strategy during those fateful December days. There were three factors, above all, that the author highlights as essential for understanding Hitler's decision. First, Nazi Germany's relationship with Japan before the attack on Pearl Harbor was not that of close, reliable allies. At one point during 1941, Schmider points out, the German government even “reached the conclusion that their would-be allies were probably seeking a better deal from the West” (264). It was only in early November 1941 that signs from Japan began to indicate to German observers that their Asian ally might be preparing a war against the Western powers in the Pacific. But even at this point, Hitler and Foreign Minister Joachim von Ribbentrop's first reaction was “to restrain the Japanese from extending their war of aggression to the USA” (266). This changed a few days later, however, when the United States finally gutted the Neutrality Act on November 13, 1941. Hitler saw this move as clear evidence that a war with America was on the horizon. Add to this the third and most crucial factor, namely that both the dictator and most of his high-level military staff agreed at precisely that time that “the Red Army was, if not quite a broken reed, certainly past the point where Allied help would be able to pull it back from the brink” (426).

What Schmider describes, in other words, is a perfect example of historical contingency. It was the coming together of these three factors at this specific moment in time that made Hitler declare war against the United States. Schmider makes a convincing case based on a careful archival reconstruction and interpretation of the events. That said, in his attempt to rationalize Hitler's strategic decisions of late 1941, the author risks overlooking at times that, in the grand scheme of things, ideology remained the central framework within which Hitler operated. The danger of this approach becomes especially evident at the end of the monograph, when Schmider argues that the “avalanche of disasters” that left in tatters the grand strategy that had guided the German war effort the day Hitler declared war against the U.S. “would have been hard for anyone to foresee” (548-549). That might be true for the nitty-gritty of how the events unfolded on the ground but not for the larger picture. The choice to go to war against both the Soviet Union and the United States within months was, in the end, a megalomaniacal one concocted by an ideological mind.