I think that at the very least our patchwork of law enforcement in the US is highly inefficient and expensive. At the worse it is largely ineffective.
The US is the largest police state* in the world. We have 50% more sworn law enforcement officers per capita than the next largest police state* in the world, Germany. Twice as many if you include unsworn private security officers.
* that isn't an oil rich city state on the South China Sea, i.e. Brunei.
Even with this large number of police we have about
twice as much crime as any other developed country, nearly five times the crime rate in Canada, ten times the crime rate of the Euro zone countries and only Russia and Brazil have higher murder rates and they are usually considered to be intermediate countries, not advanced and not fully developed.
Local control of the police means that many overlapping jurisdictions exist, that many of the police are used as revenue enhancers targeting drivers, that the most experienced police are in the relatively safe and high paying suburbs while the least experienced officers are in the high crime urban areas, that training standards vary all over the map, that the level of police corruption is higher, and that the level of professionalism in the police is overall lower than it should be.
Most countries avoid these problems by having a national police force. And yet this seems to a subject that is not even discussed in the US.
This is due, in my opinion, to an irrational fear of the federal government and an equally irrational acceptance of the failings of the most unresponsive levels of government; the middle ones between the federal and the local level; the states, townships, counties and the vast number of specific purpose regional authorities.
These middle levels of government were an 18th century compensation for the slow means of transportation and communication, problems that no longer exist.
The irony is that small government conservatives support this massive number of governments. Those who constantly harp that we should run the government like a business support a government organized with more middle management than any modern corporation would tolerate.