Complex sentence: The Office of Policy Coordination (OPC) was a U.S. covert psychological operations and paramilitary actions organization completely separate from the Central Intelligence Agency (CIA) until the two were merged in 1951.
Split into simpler sentences: The Office of Policy Coordination (OPC) was a United States covert psychological operations and paramilitary action organization. Originally an independent office, it was merged with the Central Intelligence Agency (CIA) in 1951.