 Once disembarked, the Commission assisted in effectuating the transition of police, administrative, juridical, and – most importantly – political power to American military and civilian authority.Many of the original Commission "volunteers" had, pre-war, promoted insurgent and annexationist causes, as a result of which they had caught the interest of Spanish authorities.The Puerto Rico Commission's 1 August 1898 landing at Arroyo was both the definitive manifestation and the fruition of their annexationist and pro-American goals.