Recent press reports suggest that Pentagon leaders are considering a dramatic organizational change: relinquishing the traditional U.S. role of providing NATO with its Supreme Allied Commander (SACEUR). This would be deeply unwise and potentially dangerous for the United States, as well as for our European allies. Since December 1950, when General Dwight D. Eisenhower became the first Supreme Allied Commander of the newly created North Atlantic Alliance, the position has been filled by an American. This is not spelled out in any formal document. Rather, it is a norm that has been honored by the Alliance for almost 80 years because the United States is the alliance’s strongest member. It also serves as an important sign of Washington’s commitment to European defense. And it underpins the forward deployment of U.S. nuclear weapons on the territory of select European NATO members, which remains central to extended deterrence.