The Economist Intelligence Unit (EIU) Democracy Index is somewhat pessimistic (based on 2018 scores), with only 11% of the countries of the world fully democratic--and not including the US. The most common category was authoritarian regimes. There are four categories: full democracies (20, with scores from 8-10), flawed democracies (55, 6-8), hybrid regimes (39, 4-6) and authoritarian (53, below 4). The scores are based on 60 indicators, including pluralism, civil liberties and political culture. Norway scored 9.87--that's democracy and the top 10 scored above 9. An additional 10 scored between 8 and 9. The US did not make it, and is rated a shocking 25th with a score of 7.96--a flawed democracy.
With the declining rating of democracies, it is time to look at the most extreme (and common) categories, hybrid and authoritarian regimes (92 or 55%). Key characteristics are a strong central government with limited individual/political freedoms. Rule of law is lacking with no institutional accountability. Disturbing trends include the increasing authoritarianism in important states, including Russia, Turkey, Poland, Hungary and Venezuela. China, with the largest population and soon to be the biggest economy, remains authoritarian with a matching institutional (communist) system; simultaneously, China does quite well at capitalism. [India, the other giant country, is a flawed democracy (41st at 7.23).]
Many disciplines study authoritarianism, including political science and psychology. Psychology emphasizes charismatic "strong" leaders (see "Dark Charisma") as appealing to a large percentage of the population. Anger and threats (generally emotional rather than fact-based) is a major factor, with a related single forceful leadership style. Political science sees a shift toward conservatives for authoritarian characteristics. This is also consistent with a hedgehog (not fox) mentality.
Political science has somewhat similar views of authoritarianism. First is the concept of safety over civil liberties (a key point of Thomas Hobbes in the 17th century). The world view of people favoring authoritarian leaders is on order and authority, with distrust of outsiders. In the US historically both Democrats and Republicans could be authoritarians (e.g., Huey Long, a Democrat, or Joe McCarthy, a Republican). Now the focus is almost exclusively on Republicans favoring "traditional values," favoring military solutions over diplomacy, and fearing terrorism and foreigners in general. Surveys suggest that authoritarianism is predictive of support for Trump.
Evidence from history does not bode well for this group. It seems more likely than not that authoritarian leaders become blood-thirsty monsters. Basar al-Assad, President of Syria, is a recent case in point. Apparently, his plan was to be a soft-spoken ophthalmologist in London until his brother died and he became heir-apparent to his father Hafez al-Assad as dictator of Syria. Given his exposure to the West, he was expected to be a reformer when he assumed the presidency in 2000. In this role, given the power and culture, he proved to be as savage as his father. He ordered a crackdown on Arab Spring protesters which led to Syrian Civil War in 2011. The death count has gone up and up, 400,000 by 2016. Vladimir Putin took over a struggling Russia around the turn of the century and proved ruthless and effective (true to his KGB roots). His drive for a greater Russia, which would include Crimea, Ukraine and so on, plus hostility toward the West, proved popular (at least outside of Moscow and other major cities). Opponents often disappeared or were killed in the streets. Money and power for this broad group proved compelling, while public order and rule of law did not.
Ian Bremmer, president of Eurasia Group, tweeted on April 19, 2019: "Mueller report shows how Trump wants to be an authoritarian leader. But can't be. Because the checks and balances on his power are too strong. Because his own advisors won't help him; and because he's too incompetent to pull it off."