In the Crito Socrates puts forth various arguments for why it is morally obligatory for him to obey the law. By extension, his reasons can be applied to anyone. I will outline two of these arguments and provide a little commentary on each.
In the first argument argument we will consider, Socrates is talking to Crito (his dialogue partner). Socrates assumes that he and Crito are both citizens of the state.
Question: Do we have a moral obligation to obey the laws of the state?
Argument I. The Argument from Gratitude
P1: The state has provided benefits for its citizens.
P2: We should be grateful to those who provide us benefits (i.e., it is morally obligatory to do so).
P3: We should display our gratitude by obeying the laws of the state.
Therefore, we do have a moral obligation to obey the laws of the State.
In connection with Argument I., Socrates uses an illustration of a child-parent relationship. A child should be grateful to its parents for all of the good things they give to the child (assuming, of course, they do good to their child and not evil). In the same way, we should be grateful to the state for all of the good things the state gives to us.
While the parent-child relationship may appear to be an analogous arrangement to that of a citizen and her state, it is not without its shortcomings. For example, citizens pay taxes, etc. to the state for the benefits they reap from the state. This is unlike the child-parent relationship in that children don’t usually give their parents anything in return for the good things they reap from their parents. Basically, the analogy breaks down.
Of course one could reject Argument I. by arguing, successfully, against at least one of its premises. For example, one might deny that P2 is true because it isn’t morally obligatory to be grateful to someone who has provided you some benefit (b) if you never asked for (b). While I don’t find this argument convincing, it does illustrate how one might begin to challenge Argument I.
There is a second argument that Socrates puts forward (to Crito) that deserves some attention. We’ll call this argument the Social Contract Argument. More formally, it looks like this.
Argument II. The Social Contract Argument
P1: By not leaving Athens, you’ve agreed to obey the laws.
P2: You should keep those agreements you’ve consensually entered into.
Therefore, you’re obligated to obey the laws of Athens.
There are a few things one could say in response to Argument II. For example, one might take issue with the notion of tacit agreement involved in P1 and use this to reject P1. Secondly, one might conclude that P2 isn’t always true. For example, one might decide that consensual agreements can be broken in extenuating circumstances. In the case of the state, one might not keep her end of the bargain if she feels that the state hasn’t kept its end of the bargain.
Much more could be said regarding these two arguments. However, this will suffice to provide some glimpse into Socrates’ reasons for claiming that we are obligated to obey the laws of the state.