Who has the power

[Spongebob]

How are you measuring power?  What is your metric?  That will determine whether power is zero-sum, as you contend, or not.

That's a good question.  I'm at a loss to state it empirically.  What I think of as power is who controls how people live.  For example, in the slave South, plantation owners controlled pretty much everything.  They set the rules and everyone had to abide by them.  Another example would be 19th and 20th century New York, where the mafia was so powerful that it controlled what many people could and couldn't do; to the point that they controlled aspects of the government.  I'm sure these are just two in many such groups.  And these are just recent American concepts of power.  More and probably better examples might be found elsewhere in time/space.

The reason I assert that power is zero-sum is that when power is removed from one group, it transfers to another, usually the one that intervened.  For a time after the Civil War, the occupying North held the power in the South, but then gave it back only a few short decades later.  The old plantation owners had power, lost it to the North, who then gave it back to white people in the South.  That power never went away, it only changed hands.