Basically the issue here is that for personalist regimes, both power and the daily function of the political elements of the society are held personally, whereas in institutional regimes, that power is mediated heavily through institutions which are larger than the people in them. By way of example, in both kinds of regimes, you might have a ‘Minister of Security’ who reports to the leader of the country. But whereas in an institutional regime, the minister of security does so because that is the institution (he holds an office and his office reports to the office of the leader), in a personalist regime, the power relationship depends on that minister’s personal relationship to the leader. He reports to the leader not because his office does but because he, personally is connected – by ties of loyalty or patronage or family – to the leader himself.

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One of the other reasons why personalist regimes are, I suspect, so popular with storytellers, especially as villains, is that they are easy to defeat on a personal scale. If all of the power in the regime is tied up in the personal relationships of the ruler, then defeating or killing the ruler, the Big Bad, offers at least a chance that no one else will be able to take his place and the system will collapse. That’s not historically absurd – we see it play out in succession disputes repeatedly. The death of Cyrus the Younger at Cunaxa (401) instantly results in the collapse of his revolt, despite the fact that large parts of his army were undefeated – they were there to fight for Cyrus (or his money) and with Cyrus gone, there was no reason to stay. Likewise the death of Harold Godwinson at Hastings (1066) marked the end of effective Saxon resistance to the Norman invasion, because that resistance had been predicated on Harold’s claim to the throne. In the Roman Civil Wars, the flight or death of a given Roman general often resulted in the effective collapse of his faction or the mass desertion of his troops (e.g. the surrender of many Roman senators after defeat after Pompey’s flight from defeat at Pharsalus (48) or Antonius’ army’s defection after his flight at Actium (31), in both cases happening while the ’cause’ of the fleeing party was still very much ‘live’).

And that’s a really satisfying story narrative where the hero is able to defeat the enemy utterly by doing a single brave thing on a very human scale – throwing the Ring into Mount Doom sort of stuff. And for personalist regimes, that can actually work – such regimes often do not survive succession when the charismatic leader at the center whose relationships define power dies or flees. This can actually be exacerbated by the fact that many rulers in personalist regimes do not want to have clear successors, since a clear successor might easily become a rival. Thus not, for instance, the many dictators worldwide whose succession plan is just a bunch of question marks (e.g. Putin’s Russia). Anything else would be inviting a coup.

The danger, of course, is applying that same logic to an institutional system. But since the relations of power in an institutional system belong to institutions which are ‘bigger’ than the people who populate them – power belongs to the office, not the man – slaying the Big Bad Leader has very limited effect. It might briefly confuse their leadership system, especially if quite a lot of leaders are lost at once, but institutional logic triggers quite quickly because you’ve killed the leaders but not the institutions. So the institutions quickly go about selecting new leaders, using their existing, codified institutional processes.

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In practice you could never do that with individual strikes. The only way to tear out the institutions would be through occupation – through putting troops on the ground where they could impose their own systems of control directly on the populace. Of course in many cases that approach might be ruinously costly in both lives and resources, perhaps so costly not even to be contemplated. Which is one of the many reasons it would be important at the outset to distinguish between an institutional regime and a personalist one, to avoid being in a situation where a strike at the ‘Big Bad’ has failed to achieve objectives, leaving a plan trapped between the ground forces it is unable or unwilling to commit and the inability of assassinations and airstrikes to end a conflict once it has been begun.