The Marshall Islands is a Micronesian nation of atolls and islands in the middle of the Pacific Ocean. The islands were occupied by the United States for several decades after World War II. They are now a sovereign nation. The government system is a constitutional government in free association with the United States; the chief of state and head of government is the president. The Marshall Islands, largely dependent on the United States, has a traditional economic system in which the majority of the population engages in subsistence agriculture.