It's not a very good sentence.
If you think about "the emergence of a public power" (whatever that means), then the modern state is more separated than "pre-existing patrimonial regimes."
If you think about "administrative or surveillance point of view" then the modern state is less separated than the old regimes.
In other words, you are much less likely today to have any sort of connection to your elected representative or president than a serf would have had with his lord or king. But the king would be much less concerned with regulating your existence or knowing all about your actions.
The king may have had the power of life and death over his subjects, but he didn't concern himself with how the average person lived his life. Compare to today's "lords" who regulate every aspect of our lives, from the fuel economy of our cars to the number of gallons used to flush our toilets.
Student or Learner