A new interpretation of the constitutional law of foreign affairs, as it has been developed throughout its history by presidents and by Congress.

In the more than 230 years since the Constitution took effect, the constitutional law governing the conduct of foreign affairs has evolved significantly. But that evolution did not come through formal amendments or Supreme Court rulings. Rather, the law has been defined by the practices of Congress and the executive branch, also known as “historical gloss.”

Curtis A. Bradley documents this process in action. He shows that expansions in presidential power over foreign affairs have often been justified by reference to historical gloss, but that Congress has not merely stepped aside. Belying conventional accounts of the “imperial presidency” in foreign affairs, Congress has also benefited from gloss, claiming powers for itself in the international arena not clearly addressed in the constitutional text and disrupting claims of exclusive presidential authority.

Historical Gloss and Foreign Affairs proposes a constitutional theory that can make sense of these legal changes. In contrast, originalist theories of constitutional interpretation often ignore influential post-Founding developments, while nonoriginalist theories tend to focus on judicial decisions rather than the actions and reasoning of Congress and the executive branch. Moreover, the constitutional theories that do focus on practice have typically emphasized changes at particular moments in time. What we see in the constitutional law of foreign affairs, however, is the long-term accumulation of nonjudicial precedents that is characteristic of historical gloss. With gloss confirmed as a prime mover in the development of foreign affairs law, we can begin to recognize its broader status as an important and longstanding form of constitutional reasoning.