The nature of intelligence cooperation between nation-states remains one of the most closely guarded of secrets. Nevertheless, the secret underside of alliance systems bears study for what it reveals of common perceptions of threats, degrees of mutual trust and confidence, the development of mechanisms for information exchange, and the status of intelligence within the partner states. Despite the secrecy that surrounds the subject, inspection of the inner workings of intelligence relationships can provide insight into broader patterns of cooperation.

Intelligence alliances were a prominent feature of the Cold War and the “wrestler's embrace” between the United States and the Soviet Union. Such alliances reached paradigmatic status in the British-American “special relationship,” which provided for a wide-ranging and institutionalized exchange of even the most secret and sensitive data. But the British-American intelligence alliance was forged in the fires of World War II and functioned within a shared Atlanticist culture. By contrast, intelligence cooperation between the United States and Germany had very different origins; its history testifies to the chemistry of accident and necessity.

When American occupation forces began their work amidst the ruins of the in May 1945, the idea of future cooperation between the intelligence services of the United States and a restored German government was unimagined and unimaginable. The intelligence agencies of the Third Reich lay, like the system they served, in ruins. Apart from being ground under by military defeat, Nazi intelligence had suffered from intense internecine warfare, which peaked in the final year of the conflict. Victory by the SS in this internal struggle had only intensified the collapse of the Reich’s intelligence function.