Conquest's Three Laws

From the historian Robert Conquest:

Everyone is conservative about what he knows best.

Any organization not explicitly right-wing sooner or later becomes left-wing (see, for instance, Amnesty International).

The simplest way to explain the behavior of any bureaucratic organization is to assume that it is controlled by a cabal of its enemies. 

And for more on that last law let's go to the corollaries on the Iron Law of Bureaucracy from science fiction writer Jerry Pournelle:

In any bureaucracy, the people devoted to the benefit of the bureaucracy itself always get in control and those dedicated to the goals the bureaucracy is supposed to accomplish have less and less influence, and sometimes are eliminated entirely.

With a reformulation:

...in any bureaucratic organization there will be two kinds of people: those who work to further the actual goals of the organization, and those who work for the organization itself.  The Iron Law states that in all cases, the second type of person will always gain control of the organization, and will always write the rules under which the organization functions.

In other words, any large bureaucratic organization eventually is run by those most focused on perpetuating and strengthening the organization regardless of its original intended purpose, indeed, even if it is detrimental to its original intended purpose.