Why did the US seize Pacific islands during World War 2?

During World War II, the U.S. seized Pacific islands primarily to establish strategic military bases and supply lines in order to counter Japanese expansion in the region. Capturing islands like Guadalcanal and Iwo Jima allowed American forces to launch air and naval operations, facilitating the eventual push towards Japan. This island-hopping strategy aimed to bypass heavily fortified positions, weakening Japanese defenses while securing vital locations for future offensives. Additionally, controlling these islands helped protect vital supply routes and maintain communication across the Pacific theater.