Basic Trope: A civilian agency with paramilitary forces.
Straight: StateSec is an autonomous organization that uses a paramilitary army to help keep order. It also includes administrative, research, propaganda, political sections, a personal bodyguard and elite forces. Personnel puts great emphasis on ideology.
StateSec includes every civilian security agency, all intelligence agencies, its own fleets and planets, a paramilitary group, a section of regular military loyal to the Ruler, a Praetorian Guard, Elite Troops to keep everyone in line, Special Elite Troops to keep the Elites in line, an Administrative division, a Science section, an Occult section, a Propaganda network, Judicial branch, the Horse Ridding Club, a Social Engineering committee, and its own teen groups. Hard core personnel are obsessed with their ideology, considering any other viewpoints as treasonous.
There are at least three state sec agencies and they spend as much time watching each other as watching everyone else. This was deliberately engineered by the ruler to keep them from getting out of hand.
State Security is a small special investigation division, mostly civil investigators, a few Special Ops troopers and some Tankettes. While its firepower is formidable against street thugs, the military could easily defeat it in open combat. Ideology is largely unimportant
The Special Ministry has it's own magic-using troops, but their main purpose is investigating and research (not warfare or playing politics).
State Security is a benign and rather silly imitation of a far worse organization that existed back when The Empire was forming. It consists of people who like wearing fancy uniforms and having torchlight parades and talking of the "glory days" but who do nothing more evil then start a Bar Brawl when someone reminds them of what their supposed spiritual ancestors were like. The Emperor tolerates it because it keeps his subjects happy.
The Ruler decides he can't trust the Military. To check their power, he arms his Security agency.
The Ruler decides that he needs to shape the world in his image. He creates StateSec, expanding his small bodyguard to create loyal tools to do his bidding.
State Security regularly deals with enemies that require large amounts of firepower to handle.
The Special Ministry is the only agency that knows anything about magic. Because of the paranormal nature of their enemies, The Ministry is the only ones with the knowledge / weapons that can deal with them.
The Military started off as the Secret Police. When their responsibilities expanded to include National Defense, the agency armed itself, changed its mandate and structure to become a regular armed force.
As the war drags on and The Empire slides further and further into militarism, the military's role expands until they're basically running all of society.
Subverted: StateSec has over ten thousand troopers, plus their own tanks, ships, and aircraft. However, the vehicles are obsolescent, the soldiers poorly equipped and held in low regard, and their only duty is basically glorified border patrol.
Double Subverted: After years of being a minor unknown agency, StateSec comes to center stage and becomes a major power player.
The Post Office has their own army, due to the Ruler mistakenly assuming that the Postmaster-General was part of his Joint Chiefs of Staff.
The ruler's maid has her own army. Keeping the palace clean is Serious Business!
Zig Zagged: The nature and strength of StateSec is constantly shifting due to erratic political climate.
Averted: The Dictatorship oddly lacks a StateSec, keeping the Secret Police a strictly civilian agency.
Enforced: The author writes a book that is basically World War II in Space. To keep the historical allegories, he has his Evil Empire employ a StateSec.
Lampshaded: "Seems like overkill to have the police run around with tanks."
Invoked: A character creates StateSec, hoping that it will enhance the image of his government. "And we'll have cool uniforms and every other country will respect us!"
A character creates StateSec, knowing that it could be manipulated to further the character's agenda.
A character actively encourages the formation of StateSec in order to discredit the government as a "totalitarian dictatorship".
The Four-Star Badass of the enemy army concentrates his attack on the State Sec forces knowing that they are incompetant soldiers who will be easily crushed and hoping that there will be a mutiny in the enemy camp once it becomes safe.
Defied: A character realizes the unfortunate dangers of such an all-powerful organization, and works to make sure the Secret Police never has their own army.
Discussed: Bob and Alice discuss the pros and cons of their nation's StateSec.
Conversed: "Why is it that all StateSecs seem to have the same dress code?"
Implied: The Orange Section troopers who show up in the story every once in a while wear their own uniforms (which include armbands), have their own ranks and hierarchy, can do whatever they want regardless of the law, and regular military Officers must obey them "or else". The astute reader will notice these hints, which suggest that Orange Section is a StateSec.
StateSec is more dangerous than the enemies they're supposed to fight. Their rivalry with the Military leads to greater tensions and reduced efficiency. Their zealousness may cause the populace to hate the government, which results in uprisings. And their political influence could make them a threat to the Ruler's power.
Despite their fearsome reputation, StateSec Troops regularly get slaughtered in battle. Being the "Elite", they're used to being treated like winners and are overconfident. Being led by political hacks with little or no experience does not help. Also, a bunch of street thugs or bureaucrats used for political bullying are no match for trained soldiers.
StateSec is aware of the dangers itself can pose, and takes steps not to alienate the military, people, or government. Though they may be powerful and ruthless, they're at least respected (if not loved) by everyone.
Because of the lack of military prowess, StateSec soldiers are used for garrison duty. While not as glamorous as being in battles, the Security troops are much better at policing than fighting.
Played For Drama: The story centers around a rank-and-file bureaucrat in the Empire who discovers that the StateSec is plotting to overthrow the Ruler, and must decide whose side to take before it is too late.