The illegitimate acquisition of political power is a subject that is particularly poorly understood and documented.
This is understandable, since anyone who succeeds in gaining power illegitimately is unlikely to document how they did it for fear of creating competitors who might take it from them -- not to mention the fear of undercutting their authority by revealing the illegitimate or even illegal actions that were used to acquire said power.
We can nonetheless study what is known about how power has been acquired throughout history and in modern society, hypothesize the mechanisms at work, and see if those mechanisms apply to further examples. We can also examine fiction that is widely believed to be "true to life" for possible mechanisms.
Note: This page is at present a little bit more speculative than most pages on Issuepedia, since definitive information on this subject seems to be sparse.
While examining fictional stories certainly doesn't prove anything about how illegitimate power is actually acquired or created, such stories can often suggest mechanisms that may be at work and how our belief in those mechanisms is woven into modern society.
Fictonal works illustrating the acquisition of illegitimate power include:
Many scenarios start with an imagined ideal society, in order to examine ways in which power can be created without society's consent.
In a peaceful minarchy, where individuals may do pretty much anything they want as long as they don't hurt or coerce others, someone -- call them "the warlord" -- acquires large amounts of guns and money through legitimate means. The warlord then announces a plan to take over the minarchy and install himself as a dictator, with positions of higher power for those who help him to carry out this plan (cronies). He also hires henchmen (someone willing to commit unethical acts in exchange for money).
Once everything is in place, the warlord uses the acquired coercive resources (primarily guns, cronies, and henchmen) to take control of vital production facilities. This provides him with basic needs by which to provide for his loyalists, and may also generate revenue or concessions from the opposition, if they cannot replace the output of those production facilities.
In the absence of an adequate retaliatory response from the opposition (which, presumably, does not have enough coercive resources to overcome the warlord -- and the warlord would not be likely to initiate force until he was reasonably certain that this was the case), this results in a positive feedback loop that delivers ever more power to the warlord: the more power he gains, the more he can coerce or persuade others to concede even more power.