Even in today's court, abstaining from incest is a legal standard. However, laws defining illegal incest and its punishment actually vary from place to place. While in the US incest is considered illegal, state laws concerning incest vary greatly. Hence, if Oedipus were living today and as ruler of the US or of a state within the US, he would be judged harshly by our legal system.
Some states are far more harsh when it comes to giving sentences to criminals charged with incest. Most states sentence offenders with prison terms, but depending on the state, the prison terms can range from five years to life. As ruler of the US, if Oedipus was convicted in D.C., he would be sentenced with no more than 12 years. However, if he was the ruler over one of the southern states, he would be given a life sentence. New Jersey is the only state that does not penalize individuals guilty of incest that are 18 years old or older. Also, what counts as incest can differ from state to state. For example, Rhode Island, in which orthodox Jewish communities are prevalent, does permit uncles and nieces to marry. In addition, not every state considers marriage or sexual relations between step-individuals or in-laws to be incestuous. However, every state does consider marriage or sexual relations between parents and offspring to be incestuous. Therefore, Oedipus would certainly run into legal issues, and possibly conviction, in today's society.
Towards the end of the play, it becomes very evident that Oedipus has performed an incestuous act when he, Jocasta, and the audience/reader learn that Oedipus was given to the shepherd by Jocasta, who then gave him to the messenger from Corinth, who then gave him to Polybus of Corinth for adoption, as we see when the shepherd explains to Oedipus under duress, "[the baby in question] was said to be the child of that man himself [Laius], but your wife could explain the situation best" (1196-97). Hence, we see that Oedipus is indeed guilty of incest and would be penalized by today's court.