What are the motifs in Tales of the South Pacific by James A. Michener?

Despite a lot of fun and games going on in the South Pacific, the purpose of Americans there is to win the war against Japan. This is a recurring idea in the book. As is shown in the story "The Coral Sea," there are high stakes at risk in these battles, with a danger that Japanese forces could be unstoppable and occupy places such as New Zealand and Australia. A key turning point in the story is illustrated in the story "The Cave." In this story, the PT boats are shown to be an inadequate weapon that is still used to attempt to stop the Japanese from bringing up forces down the Slot and then to Guadalcanal. The long drawn-out battle for Guadalcanal destroys the power of the Japanese to launch an offensive, and gives the Americans time to reinforce their weak forces.