Complex sentence: Truman acknowledged that it was important to settle Puerto Rico's status, and supported the plebiscite in 1952 in which they reviewed a constitution drafted for the "Estado Libre Associado".
Split into simpler sentences: Truman acknowledged that it was important to settle Puerto Rico's status. He supported the plebiscite in 1952 in which citizens could review a constitution drafted for the "Estado Libre Associado".