All or some of these elements have been present in the decline of societies that once experienced great heights of power and perhaps cultural achievements, including 5th century Athens and 3th century Rome in the classical period, the British Empire after WWII and the Soviet Union, which was in a sense a continuation of the old Russian Empire, in the 1980s. Oswald Spengler tried to capture the decline of western civilization in a book that developed a cyclical theory of the rise and fall of civilizations. Summarily rejected by Karl Popper and Thomas Mann, Spengler was widely accepted by the public in many nations that felt WWI proved the rationalism of the Enlightenment invalid.
Almost one hundred years after Spengler published The Decline of the West, people in all walks of life, from scholars to politicians are raising the question of America's decline after a century of grandeur in domains ranging from global economic preeminence to establishing the best science and arts institutions. All of this may be facing a gradual road to chronic decline. Some argue that spiritual decline is the root cause of American societal disintegration, while others see more secular threats to the Republic.
I searched the Web for stories with the titles “who threatens American democracy” and “threats to US democracy,” and discovered that many essays include the following ten categories:
1. military establishment, conventional war, and war (PR, covert, etc.) on terror;
2. government bailout of banks and corporations at the expense of the middle class and workers;
3. the Supreme Court that is out of touch with the American people;
4. economic weakness and economic inequality - the top one-tenth of 1% earn as much as 120 million people combined
5. the World Trade Organization, the UN, movement toward world government;
6. Corporate power, corporate media, corporate campaign contributions in the hundreds of millions without disclosure and transparency thanks to the Supreme Court that equates campaign contributions to free speech.
7. Religious extremism of all types, especially linked to political agendas; Islamophobia and Terrorism that has resulted in the expanded bureaucratization of domestic security and intelligence;
8. political (voter) ignorance, and interest groups that have the inside track in government;
9. the Internet, web, blogs and its various dimensions that make it easier to propagate and organize;
10. narcotics trade and crime that contributed to economic and social decline from within.
If we accept all of the above, it seems that an open society has many enemies it must confront. The biggest challenge to remain strong is to maintain sound institutions that enjoy popular support by serving the people instead of a small segment of society, a segment usually responsible for institutional decadence. There are those who dismiss all of the above causes of decline and maintain that one reason that America achieved its cohesiveness as a society and great power status because of its very strong religious tradition, especially conservative Protestantism currently in decline owing to secularization of mass culture.
Besides the spiritual thesis, there is also the 'human nature' thesis regarding leading cause for societal decline. One very interesting article argues that the most basic threat to democracy is the human brain that “is predisposed to use information to confirm their existing beliefs, which makes democratic governance impossible.” If we accept that human nature as inherently atomistic and irrational guided by instinct without regard to the welfare of others and the community, then the human brain with its predisposition to the irrational and atomistic is indeed the obstacle to democracy.
If we also accept the assumption that competition and private accumulation of wealth power, prestige, etc. in the social, economic and political spheres promotes self-interest at the expense of the greater good, then we have another obstacle to democracy functioning harmoniously for the welfare of all its citizens. But all of this is predicated on the definition of “democracy,” a concept that many people equate with free enterprise and individual pursuit of wealth (Adam Smith and Liberal followers), others with social welfare and the pursuit of the greater good for the greatest number (utilitarian democracy), others with human rights and social welfare (social democracy), others with basic freedoms such as press, assembly, etc.(Libertarian), others equating democracy with voting.
Of the ten categories listed above as “threats to US democracy,” clearly all of them and many more are real, depending on the individual’s definition of democracy, and on value systems that spell out not only what democracy is but what it is not. On the broader question of internal or external factors that cause the demise of a democratic society, here we can look at historical experiences of countries that were “to some degree open societies,” countries that enjoyed aspects of democracy but lapsed toward some model of authoritarianism.
In the cases of interwar Italy, Germany, and Japan the causes of abandoning pluralism for an extreme form of militaristic ultra-authoritarianism rooted in ultra right-wing ideology were internal, although external causes served as a pretext to convince the public of the need for a militaristic/authoritarian regime. If indeed people care more about safety and security, or at least if the media and their political, business, and social leaders convince them that nothing matters more than safety and security, people will voluntarily surrender any commitment to democracy for the perceived guarantee of safety and security.
If the US moves increasingly toward a more authoritarian model under the political shell of “democracy,” as it could if in the future it faces more and deeper economic contractions that result in an increasingly smaller and weaker middle class, the cause will not be the UN, the WTO, Islamic “terrorism,” rogue nations like North Korea, etc. The dynamics of modern society have some similarities with the 17th century when Thomas Hobbes wrote the Leviathan. Therefore, if a modern American Leviathan (authoritarian regime) emerges it will be an expression of contemporary society confronting a social and economic structure that is unraveling.
The segment of society that has the power to mold public opinion and convince them that Leviathan means “salvation” from self-destructive proclivities of an otherwise irrational public, will move society away from the Jeffersonian model that some equate as the ideal toward one that projects an image of narrowly-defined democracy and equates it with “the freedom to shop, to enjoy safety and security, and vote for politicians who represent the same institutions”" a model behind which rests an authoritarian/police/military state.