The natural state of nature is the seemingly chaotic movement to balance.  Hurricanes draw warm temperatures from the tropics to the north hence achieving balance, albeit violently.  The number of predators increases and decreases to match the population of prey which also reacts inversely to the population of predators.

In democracies, the political trends also swing left to right and back again.  This movement is caused by people who feel that the other side has pulled too far from their own view of ideal.  The Radical Moderate helps the minority pull back to the middle until they become the majority and then pulls the other way.  The center is the perfect balance point.