There has been a dramatic rise in the political power of belief system's leaders in the past half century. This is especially true in the case of those with a religious foundation.
The polarization in both economic and social policy has become extreme. As this site illustrates it is difficult for one side to even listen to those with an opposing view.
A little history and then some observations, below:
Before the Enlightenment, political power was almost entirely in the hands of an hereditary aristocracy and the Church. Starting in the 17th Century this started to shift. The power of the Catholic church in Europe was diffused by the rise of Protestantism. Further east the Ottoman Empire started to weaken. At the same time the industrial revolution led to the rise in power of the mercantile class and the installation of representative governments. The decline in a universally accepted cultural framework based upon religion led to a series of new ideologies based upon economics and natural science. Some of the most lasting have been utilitarianism, communism, socialism, social Darwinism, and libertarianism.
What these have in common with traditional organized religious belief is the claim to be able to explain all human behavior, and history, by reference to a small set of fundamental, self-evident, truths. Where Christianity refers back to original sin, so Rousseau refers back to the Noble Savage. Others, like Ayn Rand, propose inherent selfishness, while Marx sees greed as the underlying basis of human behavior.
Religions seem to have several universal characteristics. They all have some sort of creation story, they all have stories of supernatural events having occurred in the past, and they all refer to rules of conduct given to mankind via some intermediary. During the age of the Enlightenment these rules of conduct were implicitly included in the laws of the country, but the actual implementation and enforcement was left to secular governments. Recently we have seen some moderately successful attempts to reverse this trend. The most dramatic being the installation of Islamic religious leaders into local governments in places such as Iran. Many other Muslim countries now have strong religious parties which are gaining political power as well. This trend can be seen stretching from Algeria to Indonesia.
In the Christian world the US has become the most visible example. There has been an unprecedented increase in the interaction between organized religion and political parties. Where in the past a typical mainstream Protestant candidate only had to echo the conventional religious platitudes, they are now being required to make specific pledges to promote detailed religious programs when elected. The interaction is also going the other way, with government funds being given to explicitly religious organizations for quasi-secular social service programs.
It seems that there is something in human nature that wants to be able to fit life into a simple framework. During the heyday of Marxism, everything could be explained by the conflict between capital and labor, for example. These days neo-con economists see tax policy and the elimination of government-administered social programs as the cure for society's problems. The trouble is that simple, universal, answers to everything are never adequate. In order to maintain their frameworks, facts which don't fit the narrative are suppressed or distorted. The leaders of these movements have an incentive to do this, since only by keeping their followers uninformed can they maintain their positions of power.
The question is why do followers allow themselves to be misled? Are humans so weak minded that facing reality is too difficult and we must substitute ideology as a shield?
A study of history can do much to enable people to overcome this need for simple answers. By studying how similar situations in the past played out, lessons can be drawn that apply to the present. Once the source of the spread of cholera was discovered, the same lesson could be applied to many other bacterial diseases. Ineffective practices using prayer were replaced with sound public health policies. Unfortunately, things are not so clear cut with economic and social policy. The effectiveness of religiously inspired sex education programs can only be determined by large scale social monitoring. The effects of tax policies are even harder to correlate to specific outcomes. But the reliance on belief rather than reality is never a good way to solve society's problems. Those that substitute belief systems for reality are at a disadvantage compared to other societies.
It is a minor tragedy that Iran has become a theocracy. Seventy million people have been thrust back 100 years in terms of social and industrial development. If the US continues on a similar track the tragedy will be much larger. Not only is the population larger, but there is the loss to the world in terms of development in science and engineering as beliefs replace reality. Promising developments in bio-engineering and energy technology are being hampered. Other countries may take up the slack, but progress will be slower and the US will lose its ability to compete. As Katrina showed, ignoring a problem does not make it go away.
Are we planning to become a second class power as the price for supporting imperfect ideologies? Is our need for belief systems so strong?