Final answer:
The Central Intelligence Agency (CIA) worked covertly to assure a communist defeat in the election.
Step-by-step explanation:
The newly created USA agency that worked covertly to assure a communist defeat in the election was the Central Intelligence Agency (CIA).
The CIA was established by Congress in 1947 as part of the National Security Act in response to the Soviet threat. Its role expanded from intelligence collection to covert action, including operations to overthrow leftist or unfriendly governments. The CIA played a growing role in the Cold War, conducting secret military operations based on gathered information.