By a September 17, 2019 Order (Order), the German Federal Constitutional Court (FCC or Court) rejected challenges to Germany's military involvement in anti-Islamic State of Iraq and Syria (ISIS) operations in Syria. This outcome was expected and was as such insignificant. What is significant is the FCC's reasoning. The Court used the Order to clarify the constitutional roles of parliament and the executive in German foreign affairs. And it included an intriguing pronouncement on the scope of Article 51 of the UN Charter, which adds a fresh perspective to the polarized debates about self-defense against nonstate actors.