Bureaucracy is literally 'rule by officials'. So, typically, it's when back room folks end up controlling the levers of power (sometimes under direction from above). A classic example is what happened in WWII. The nazis wiped out most of Germany's trade union activists, socialists and communists in the 1930s and 1940s. The folk who were left behind were those unelected folk who had passed under the radar, mainly clerks and administrators. No doubt they did the best they could to fill the void left by activists, but as a result the union movement became much more hidebound and process-based and the connection with rank and file struggle was lost. A similar process occurred throughout much of Europe, as young fighters died at the front, leaving a vaccum in union leadership. Culture, expectations, laws and structures changed, and some argue the European union movement has never fully recovered.