A fairly common trend seen in OTL is for an organisation founded as a political underground movement to gradually metamorphose into a criminal group. I suppose that they start stealing from the (corrupt, despotic, of course!) current regime they are opposed to, purely to fund their subversive operations naturally...and then one day they forget they had any cause to start with and the criminal operations become an end in themselves.
A prominent OTL example: the Chinese Triads are the descendants of the Three Harmonies Society, one of several underground movements in the 18th century dedicated to overthrowing the Qing dynasty and restoring native Han rule.
We're now seeing something similar happening with the IRA and some African acronym-happy rebel groups.
So, what other political underground movements could have taken the same route? How about the Jacobites turning into a Scottish Mafia? If the Nazis had won/stalemated WW2, would the same have happened to the French Resistance?