I want to offer here some general thoughts on the three basic political philosophies of conservatism, liberalism, and radicalism. This post will briefly (and very inadequately) trace the their historical development in Europe and America in the past, which should help us to understand the present situation, and possibly also what the near future might look like.
I begin by stating the obvious: human beings are naturally conservative, meaning 'prefering the status quo', in that we are creatures of habit and for the most part prefer things to remain the same. One extremely simple example is that church members almost always sit in the same place in church. And if a visitor sits in their place, they feel that something is wrong. Expand this to all kinds of social patterns, and the point is made. But this 'natural' conservatism is not the same thing as 'political' conservatism.
In Medieval Europe, the political pattern that became accepted by virtually everyone was throne and altar. Kings ruled in the temporal realm, and the Catholic Church ruled in the spiritual realm. This became political 'conservatism' par excellence in pre-Enlightenment Europe. Any political opinion or theory that opposed this was non-conservative and thought to be upsetting to the permanent order of things.
With the rise of first Puritanism, then the Age of Reason and the Enlightenment, different non-conservative ways of thinking about politics began to gain currency. In England, the Puritans in the 17th century argued for Republicanism and, for a few years, overthrew the King in England and established the Commonwealth. In Puritan thought in general, however, the Church would still have a great role to play in running things, only now it was the Puritan Church of Reformed Christianity. So one autocratic rule was replaced by another.
Later, in the 18th century, John Locke, Adam Smith, Montesquieu, Voltaire and other European intellectuals elaborated on what the English Puritans had begun and developed what would become the original 'liberal' political perspective, which argued for more 'liberty' and freedom: in politics, in the economy, in culture and religion. This 'liberal' political position especially grew in England during the 18th century, resulting in a strong Parliament to counter the power of the King, freedom of thought and press and religion, a freer market economy, and so on. This 'liberalism' migrated to America and became the dominant political position during the American revolution, resulting in the Declaration of Independence, the Constitution, and the Bill of Rights.
So it is actually quite accurate to say that 'liberalism' (as understood above and not in its modern sense) was the founding political philosophy of America. It became our 'conservatism', so to speak, in the sense that it was our original status quo, and to defend it was the American 'conservative' position. So one could call our original political philosophy, 'conservative liberalism' or 'liberal conservatism.' It stressed small, representative government, freedom from arbitrary power, civil liberties, private property, due process of law, separation of church and state, and so on. Within this overall American consensus, the 'conservatives' tended to be the Federalists, who were often Puritans or high-church Anglicans and oriented to a little more active and centralized government and manufacturing, versus the 'liberal' Jeffersonians, who were either Enlightenment Deists, broad-church Anglicans or free-church Methodists and Baptists, and wanted less central government, more independent farmers, more individual 'liberty'.
At the same time as American conservative liberalism became the norm, the radical Enlightenment Jacobinism of the French Revolution was the first modern 'radicalism', opposed as it was to both the European conservatism of throne and altar and the European liberal tradition. It was a more absolutistic perspective, wishing to thoroughly transform the society and culture to conform to the ideals of the French 'philosophes' like (e.g. eliminating Christianity and replacing it with the Religion of Reason), and was thus a very real forerunner of the communist/socialist revolutionary philosophies of the 19th century, developed first by the German Karl Marx.
In the 19th century, the American 'conservative-liberal' position was challenged by the socialist revolutionary position coming out of Europe. Also, the rise of industrialization led to the rise of the huge corporations and wealthy on the one side, and urban worker masses on the other. This move away from rural agrarianism to urban industrialism changed the political situation fundamentally, leading to a complete social darwinist laissez-faire philosophy on the one hand or industrial socialism on the other (both of which were more forms of radicalism). One can see here how fundamentally the social and philosophical development of the 19th century changed the American political environment and made the political labels of 'liberalism' and 'conservatism' less useful.
At the same time or just slightly later, across the ocean, in Russia, the rise of Soviet Communist radicalism led to an equal and opposite reaction in Germany, France, and Italy called Nazism/Fascism, both of which were forms of political absolutism, totally alien to the original American political philosophy.
After the Crash of '29 and the Great Depression, a new coalition and approach to American politics developed under Franklin Roosevelt called the New Deal. It was to become known as 'liberalism', but it was actually something new: a mixed philosophy of private property and market economy, some nationalization, government regulation of finance and industry, union recognition and support. In other words, it was not a pure philosphy of conservatism, liberalism, or socialism, but a sometimes awkward mixture of all three. (Arthur Schlesinger Jr. referred to it as 'the Center'.) I think it can be compared usefully to the 'social democracy' that developed in some northern European countries around the same time.
For a while, American 'conservatism' disappeared as a coherent political philosophy, until its resurrection under the intellectual William F. Buckley after WWII, who brought a coalition of libertarian individualists, throne/altar conservatives, anti-communist hawks, free-enterprise industrialialists, nationalist patriots, and finally, religious social conservatives together in one movement, which finally took over the White House in 1981 under Ronald Reagan. It is that coalition that is now falling apart after basically a generation in power (with a brief interregnum under Bill Clinton who, acting as a 'neo-liberal', served as a mediating figure between Reagan Conservatism and whatever was left of New Deal liberalism at that time).
I think in these first years of the 21st century in America, we are returning to a kind of New Deal 'liberalism', that will have to be updated, because it is a different time and the world has changed. Obama could be compared possibly to F.D.R., I believe, and it's amazing that we are facing a financial crisis some are likening to the Great Depression. (If this becomes true, I hope that he doesn't take us into the equivalent of World War II, because that could well be the end of us all.)
What a chastened and reformulated 'conservatism' will look like in the future is yet to be determined. How the various strands of conservative thought will reconfigure so as to cooperate and regain political power is hard to see at this point. There is no doubt, however, that about half the population (perhaps now somewhat less) remains wedded to some kind of conservatism (and in some cases, absolutism), even if there is no coherent philosophical position or even a leader. Will this be the role of Sarah Palin in the future? Does she have that kind of intellectual heft and political staying power? I'm a bit dubious on that point, but we shall see. (Newt Gingrich continues to vie for that leadership role, but he has not proven that he is viable politically.) But other persons, perhaps more intelligent than she will no doubt appear, since America has always had an opposing political movement to keep the status quo honest.