For Lord of the Flies as a political allegory, one need only to look at the state of the world at the end of World War II. The world was divided into two camps the free world and the Soviet Union, much like the camps of Ralph and Jack. In addition, the postwar Cold War Era suffered from fears of atomic destruction. Lord of the Flies shows the world at the brink of atomic destruction. The novel serves as a warning to the leaders of the world.
Lord of the Flies is also a religious allegory of the Garden of Eden. It was a perfect island with good food, good weather, and good water. The beastie is the snake in the Garden that lures (tricks) the others to not hold up to their duty. The parachutist and Piggy represent the fall of mankind. Jack and Ralph are very much like Cain and Able. Simon is a Christ figure who sacrifices himself to save them.