At the state level, yes. *But not at the federal (U.S.) level. These distinctions matter.

Ok. I'm Canadian, so all US law blurs together to me (especially since in Canada, criminal law is under the sole jurisdiction of the federal government).

In the US it's a mix.

Quoting from a recent post[1] on a law professor blog regarding the relationship between the states and the federal government on criminal matters:

"...[T]he states and the federal government are not exactly co-equals in the criminal law sphere. The states have general police powers while the federal government has limited powers; the states inherited the common law while the federal government must enact statutory offenses."

[1] http://www.volokh.com/2012/08/03/can-federal-border-patrol-a...

Most criminal prosecutions in the US happen at the state level.

Well, in Canada all criminal prosecutions happen at the provincial level -- the Federal government defines the criminal law, but the Provincial governments are responsible for the "administration of justice".

Which can make things interesting when the governments don't agree on whether something should be illegal or not...

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.