Complex sentence: Guatemala's economy, heavily based on coffee and sugar exports, relied on the exploitation of indigenous labour and land and a democratic regime and Marxist insurgencies posed a direct threat to the political and economic elite as well as their main trading partner--the United States.
Split into simpler sentences: Guatemala's economy, heavily based on coffee and sugar exports, relied on the exploitation of indigenous labour and land. A democratic regime and Marxist insurgencies posed a direct threat to the political and economic elite as well as their main trading partner--the United States.