"The Long Arc of Legality" shows that law is not just about rules but also about moral principles. By looking at how laws interact with fundamental ideas of legality, the researchers argue that officials need to have moral reasons to enforce laws. They bring together different philosophers to discuss how laws get their authority from social agreements. The study suggests that international and constitutional laws are crucial in understanding the philosophy of law. It also emphasizes the importance of considering the political context of laws and how they shape our sense of right and wrong.