Complex sentence: In May 1952, Jacobo Árbenz enacted Decree 900, the official title of the Guatemalan agrarian reform law, which convinced the US government that the Guatemalan government was being influenced by communists.
Split into simpler sentences: In May 1952, Jacobo Árbenz enacted Decree 900, the official title of the Guatemalan agrarian reform law. The law convinced the US government that the Guatemalan government was being influenced by communists.