There is US Federal criminal law, and then there are the criminal laws of each of the 50 US States. Federal crimes are usually more serious (like espionage), but sometimes are just a matter of federal courts being the most appropriate venue (like copyright).
There are some standards that are widely applied across the states (like the MPC, some model jury instructions), and obviously the legal issues are very similar, but there are definitely major important differences between the states; for instance, groping a 17 year old in Alabama might be an aggravated sexual battery crime, but doing the same thing in Oregon might be a basic sexual assault.
There are some standards that are widely applied across the states (like the MPC, some model jury instructions), and obviously the legal issues are very similar, but there are definitely major important differences between the states; for instance, groping a 17 year old in Alabama might be an aggravated sexual battery crime, but doing the same thing in Oregon might be a basic sexual assault.