Since Plato wrote of political obligation in his dialogue Crito, obligation in general has been of ongoing interest to philosophers. In that dialogue, Socrates argues that he was under an obligation to obey the laws of Athens and comply with a sentence of death. During the course of the argument, he raises and offers solutions to many of the central issues about obligation that philosophers still puzzle over. For instance, how can obligations have the grip on us that they do—in some cases, so that we are willing to die rather than not fulfill them? What is the nature and justification of moral and legal obligations? Do we have an obligation to obey the state, and if so, why?