Pulp Police

[Cory]

The ranks are as you have given. Chief is an administrative position - the head of the department. Each municipality has its own rules for handing out ranks and in some small communities they may be awarded for length of service or in lieu of a pay raise.

A commissioner is usually a political position that oversees the department on behalf of the mayor and rarely replaces the chief but instead adds an additional layer of bureaucracy.

Plain clothes is also at the discretion of the department. Since WWII it seems most US detectives wear suits while working.

All of the above is for municipal police forces. A sherrif is usualy an elected position and is the top law enforcement official for a county. All of the other law enforcement in his office are his deputies. A sherrif or deputy retains power throughout the county so in cities there are two law enforcement agencies, though in most towns and cities the sherrifs dept. usually leaves things up to the city police.

[Hammers]

I once asked an American friend to explain the differences in jurisdiction and responsibilities between municipal, local, state and federal police, the highway patrol, the FBI, the CIA, the National Guard, the Secret Service, the Federal Marshalls, Sherriffs and Deputies, the Texas Rangers, the Border Patroll, the Park Rangers and Highway Patroll. He lost me at "Well, it works like this..."

[revford]

In the UK, you'd have:

Uniformed:
 * Constable
 * Sergeant
 * Inspector
 * Chief Inspector

For plain clothes police, just add Detective in front of the title.  So Inspector becomes Detective Inspector.

All uniformed titles are abbreviated by adding a P for police in front, so Constable becomes PC.  All plain clothes titles are abbreviated as is, so Detective Chief Inspector becomes DCI.

Before the 90s, any female Officer would have a W for Woman added to the abbreviated title, so a female Constable would be a WPC.

I hope that helps.  

[Ironworker]

I once asked an American friend to explain the differences in jurisdiction and responsibilities between municipal, local, state and federal police, the highway patrol, the FCI, the CIA, the National Guard, the Secret Service, the Federal Marshalls, Sherriffs and Deputies, the Texas Rangers, the Border Patroll, the Park Rangers and Highway Patroll. He lost me at "Well, it works like this..."

I don't understand all the jurisdictions and I live here.  The National Guard is part of the military.  It replaced the state militias after the Civil War putting them more under the control of the U.S. military.  A governor can still call them up in the case of an emergency but I'm pretty sure he is not their commander in chief since they are under the command of the U.S. military.

[Cory]

And to add to the confusion we still have the sherrif's posse.

I was deputised into a sherrif's posse one afternoon, the instructions were along the lines of "No one carry a gun, I'll arrest any SOB that shoots anything. Just shout if you find something, run if they shoot at you, and do as the guy in the John Deere hat says."

Thankfully we didn't find the guys.

[Ironworker]

I'm pretty sure marshals can still form a posse as well.  

I'm really supprised even in this day that any sheriff would send unarmed men to look for armed criminals.  Wow.

[fastolfrus]

I'm really supprised even in this day that any sheriff would send unarmed men to look for armed criminals.

But every fisherman or hunter uses bait ?

[Plynkes]

Also in Blighty you have 'The Specials', that is to say the Special Constabulary. These are part-time volunteer coppers.

Specials are sometimes mocked due to their 'weekend warrior' sort of status, but I believe they have all the same powers as the normal Old Bill. I've mostly come across them as extra security at football matches.