As it exists, they arrest and charge based on state law, unless they have something federal to charge. Hypothetically, you could model it off of migratory wild

As it exists, they arrest and charge based on state law, unless they have something federal to charge. Hypothetically, you could model it off of migratory wildlife enforcement, with dual jurisdiction, where a violation of a relevant state law automatically becomes a federal offense, and vice versa, and agents are typically officers of both the state and federal government. Then the federal judiciary could fulfill the need where locals fall short. No private prison or judicial system needed. But it would be much more ideal if the prosecutors would just do their jobs.