This posting offers examples of how United States' foreign policy sometimes involved backing undemocratic regimes in the effort to contain communism. Resources are also given.
Although the topic is vast, I offer some examples about how America supported undemocratic regimes in an attempt to contain communism. Please allow these ideas to guide you:
First, you might apply examples from the US-backed Somoza Dynasty in Nicaragua. Please note how their power came from "three main sources: the ownership or control of large portions of the Nicaraguan economy, the military support of the National Guard, and his acceptance and support from the United States" (http://www.spartacus.schoolnet.co.uk/COLDsomoza.htm).
Please also note that their rule begin with Garcia Somoza (1937 - 1956) who showed lots of corruption such as
"gambling, prostitution, smuggling, and other forms of vice" (ucis.pitt.edu/clas/.../history/somoza/Hist-Somoza-dinasty.pdf). Luis Somoza (1957 - 1967) was also supported by America. Research shows that "Luis Somoza Debayle's anticommunist stance won government favor and support from the United States. In 1959 Nicaragua was among the first nations to condemn the Cuban Revolution, and the Nicaraguan government played a leading role in the Bay of Pigs invasion
of Cuba in 1961, allowing the Cuban exile brigade to use military bases on the Caribbean coast to launch the failed maneuver" (ucis.pitt.edu/clas/.../history/somoza/Hist-Somoza-dinasty.pdf).
As you highlight the dynasty and the American connection, you might also mention Anastasio Somoza Debayle (1967 - 1979) who was also corrupt. He used "his public office for personal enrichment" (ucis.pitt.edu/clas/.../history/somoza/Hist-Somoza-dinasty.pdf). His tenure also invoked "extensive pillage, arbitrary imprisonment, torture, rape, and summary execution of hundreds of peasants" (ucis.pitt.edu/clas/.../history/somoza/Hist-Somoza-dinasty.pdf).
In terms of Guatemala, you might also reference how America also supported Castillo Armas; he was "but first in a line of Guatemalan presidents, all supported by the United States, who in the name of anti-Communism have ruled by terror and repression" (http://www.thirdworldtraveler.com/American_Empire/Eisenhower_Guatemala_LFE.html).
In addition, another ...
This posting shows how America's attempts to contain Communism often failed.