The following will offend or be old-hat to some, but maybe be of interest to others. I type it to help give a bit of context to the young'uns, because most of us live in relatively stable countries and may be fuzzy about some of the underlying mechanics of less stable ones.
It is a crude paraphrase of part of a book written by a GRU defector discussing some foreign "technical assistance" he had been involved in. It was written long after WWII, but as they say, there is nothing new under the sun. His account was internally consistent, and correlated to things I had seen mentioned in other contexts (i.e. the US invasion of Iraq), but I have no first hand experience in such things and will happily defer to those better informed.
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All regimes require at least a small militarized police force to protect its office holders against individuals who may be trying to impress Jodie Foster, but regimes that have reason to fear a military coup have a different problem; how to protect The Boss against one or more generals who might want to take his place. One strategy is to raise/designate a special branch of the armed forces to protect the regime from the rest of the armed forces. Call it the "presidential guard", "republican guard", "protection echelon", or something along those lines.
The Guard gets the best training, the best equipment, and is extensively vetted for and focused on loyalty to the regime. It is stationed in or near the seat of government, and may be personally headed by The Boss or one of his children.
Since you will be asking it to fight other parts of the armed force, you distance it from the rest of the armed forces by special uniforms, rituals, and recruiting. It is given special privileges, both to tie it more closely to the regime, and to distance it from the rest of the armed forces. If The Boss leads The Party, expect to see a blurring between The Guard and The Party.
Efficiency and over-the-top displays of loyalty to the regime are the key desirables. Those that do well become a pool of management talent (aka party stooges) to be used in other fields. Because of this and because of the extra privileges it attracts those with ambition and especially strong demonstrated loyalty (real, or feigned for self interest).
In times of external conflict, they are among the last to actually fight because reducing their strength/loyalty by losses could prevent them from being able to perform their primary function of staving off other parts of the armed forces who might be tempted to settle for a negotiated solution (which includes putting the skids under The Boss). When the are encountered late in the game (so to say), they are a noticeably better equipped/trained/motivate opponent.
Since they are more strongly tied to the regime (which will literally die if the conflict is lost) than the state (which will, by and large survive even if the conflict is lost) they are more likely to do desperate things to win. Being selected for over-the-top loyalty and indoctrinated to disdain the traditions of the rest of the armed force, The Guard is more likely to be involved in things that later get them hanged for war crimes (or shot on sight).
Regimes that do not fear a military coup find other things to spend their resources on and do not maintain a guard of this kind.
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One also wonders how much his account was camped up for book sales, because I don't expect he was still getting his pension rubles. The word of a defector is, by definition, suspect.
If "Brevity is the soul of wit", I clearly have none.
