Ralph is an example of a traditional authority figure of the civilized world, rational, reasonable, and concerned with legitimate use of authority for the common good.
The politician that seems most relevant to the portrayal of Ralph in Lord of the Flies is Neville Chamberlain (1869 – 1940) who was Prime Minster from 1937 to 1940. He is best know for his attempts to appease Hitler and try to use diplomacy to make peace with Nazi Germany, drastically underestimating Hitler's fanaticism and ambitions. Like Ralph, a moderate and reasonable character, his major failing was an inability to understand people whose motivations were fundamentally irrational or extreme.
Jack is an emblem of the charismatic leader who sweeps into power by arousing strong, primal emotions and playing on rage and hatred and encouraging tribalism and violence as methods to maintain power and social cohesiveness. The contemporary leaders of the Islamic State such as Abu Bakr al-Baghdadi, Hitler himself, or Genghis Khan might be considered similar in character.