G.K. Chesterton wrote that “The business of Progressives is to go on making mistakes, the business of Conservatives is to prevent mistakes from being corrected.” This was certainly true of the people who called themselves conservatives in Chesterton's day, and is even truer today. But it has not always been true.
As a political term, “conservatism” came about during the 18th century. A conservative then was one who wanted to conserve Europe's waning ancien régime (I use the term in reference not only to pre-revolutionary France, but to all of pre-modern Europe) -- with its absolute monarchy, feudal economy, entrenched aristocracy, and powerful clerisy – against the challenge it faced from rationalists, philosophes, liberals, and radicals. In the end, of course, the conservatives and the ancien régime lost every significant battle, and were often deposed violently by the modernists. (1776, 1789, 1848, 1917.) Conservatism survived as an ideology, but conservatives approached the changes brought about by modernity differently.
The first generation of self-conscious political conservatives fell into two camps. One camp, preeminent in the Anglo-American world and typified by Edmund Burke, justified the ancien régime pragmatically. Burke might critique the French Revolution on the grounds that all radical and revolutionary changes are likely to end in disaster, or he might justify religious and monarchical traditions as “useful lies” conducive to social stability. Another school, represented chiefly by continental European thinkers like Bonald, Müller, and Donoso Cortès, argued against political modernism on moral grounds. For them, the spirit of the French Revolution was not foolish or unrealistic, but actively evil. For instance, they might argue, as Maistre did, that the Jacobin Terror was God's retribution on France for overturning a divinely-mandated social order.
Between the French Revolution and the end of World War I, the chasm between English pragmatists and Continental moralists grew. While the latter still wanted to restore a pre-modern social order, the former, having discovered that their arguments could be used to defend the new order just as effectively as the old, opted for reformism and allied themselves with the classical liberals. Thus, 20th-century thinkers like Hayek and Oakeshott used Burkean arguments to justify the industrial capitalism and liberal democracy against which the first conservatives had fought. The liberal-Burkean alliance still comprises the mainstream political Right in virtually all of North America and Western Europe. Because the pragmatist party line fit the Zeitgeist while the moralist party line did not, pragmatists had gained complete hegemony by the middle of the 20th century. The tiny moralist minority was either ignored or denounced as fascistic, bigoted, and reactionary. The “Alternative Right” which Richard Spencer has worked to give a voice on the Internet, if construed broadly, can plausibly be described as an atavistic moralist resurgence against the pragmatist establishment.
Now I'm a dyed-in-the-wool Continental moralist, and as such feel very uncomfortable with the word “conservative.” For one thing, it's virtually synonymous with Burkean pragmatism nowadays. For another, it implies that I want to conserve some existing arrangement. As implied, I don't. The original counterrevolutionaries could say that they wanted to save what remained of Europe's soul, but I can not, for that soul is gone now. It can not be conserved -- only restored.