The Battle of Guadalcanal was one of the first prolonged campaigns in the Pacific Ocean theater of World War II. It strained logistical capabilities of the combatant nations. For the U.S., this need prompted the development of effective combat air transport for the first time. A failure to achieve air supremacy forced Japan to rely on reinforcement by barges, destroyers, and submarines, with very uneven results. Early in the campaign, the Americans were hindered by a lack of resources, as they suffered heavy losses in cruisers and carriers, with replacements from ramped-up shipbuilding programs still months away from materializing.