Under the consensus that democracy is the least bad form of government, what are the conditions that make a country democratic or non-democratic is a question that has been raised and tried to answer for a long time. To answer these questions with empirical data, this paper synthesizes documents in the Scopus database published from 2013 to the present and highlights how current knowledge answers these questions: 1) What is democracy? 2) Why should the country be democratic and shouldn't be undemocratic? 3) What are the characteristics of a democratic and non-democratic country? 4) What are the conditions that make developed, developing, and underdeveloped countries democratic and undemocratic? And lastly, 5) What can be done to make the country's democracy sustainable? The answer to each question is explained and discussed accordingly.