sheriffs or constables ...
comparable to Local police are they not ?
The whole concept of "law enforcement" has changed radically over the years. Once you have a standing police force that is supposed to "protect people" (as opposed to simply arresting them for prosecution when they actually commit crimes), you have an entire industry in place that is now focused on treating ordinary citizens as potential criminals -- in the name of "protecting them" while taking money out of their pockets to pay for this service.
You can go back through the history of this country and see what exactly constituted "law enforcement" at any given time. For generations, the classic symbol of law enforcement in America was the rural county sheriff. His role was very different from what police officers do today. There was never any illusion that people needed a sheriff to protect them -- since an armed citizenry was perfectly capable of protecting itself. In fact, the original role of a law enforcement officer was to protect accused criminals from law-abiding citizens -- by taking those criminals into protective custody where they awaited trial through a legitimate U.S. legal process.