During the fight against al-Qaeda, affiliated groups, and states supporting Islamist terrorism, progressive critics poured scorn on the Bush administration for allegedly shredding the Constitution and trampling on international law. Prominent among those progressives was then-Senator Barack Obama, who rode the train of their anger to the White House. His frequently harsh and uncompromising words suggested that the questions of law that the U.S. faced in combating jihadists who proclaimed holy war on America — and waged it in violation of the international laws of war by disdaining to wear uniforms, concealing their weapons, targeting civilians and civilian infrastructure, and seeking weapons of mass destruction to carry out their schemes...