Jonah Goldberg writes about Fusionism, Sixty Years Later in the 60th Anniversary issue of National Review:
That is why conservatives in America are so different from the conservatives of Europe — especially continental Europe — or anywhere else. Comte Joseph de Maistre, the quintessential European conservative, sought to conserve the absolute rule of Church and Throne. The American Founders sought to overthrow even the partial rule of Church and Throne. And therein lies all the difference. In Europe, conservatism was understood as the opposite of classical liberalism. The reverse was the case in America, as Friedrich Hayek observed: “What in Europe was called ‘liberalism’ was here the common tradition on which the American polity had been built: thus the defender of the American tradition was a liberal in the European sense.”
Modern conservatism was born from the shock of events — two total world wars punctuated by a peacetime effort to import Bismarckian socialism to our shores, not to mention the long march through the institutions of Marxists, Deweyan progressives, secular humanists, et al. As the conservative movement matured, it sought out the ideological tools and weapons necessary for the counter-assault that would liberate the principles upon which this nation was founded. Yes, conservatives borrowed heavily from the libertarian tradition, but they also borrowed from the religious, patriotic, and moral arsenals of the Founders. That is why the libertarians have stood apart like Coptic Christians, who claim a lineage and authenticity that needs no sanction from the larger, more powerful, and more syncretic Catholic Church.
Earlier in the piece he writes:
It is a peculiar irony that a movement that seeks to conserve the best of the past is one of the youngest political movements in America. Socialism, progressivism, anarchism, and environmentalism have far older pedigrees than conservatism does. The American variants of socialism go back to the Shakers and even Thomas Paine (albeit tenuously). Progressivism is a cousin of socialism but nonetheless has its own family tree stretching back to Auguste Comte and John Stuart Mill. Anarchism in the West has roots going back to Diogenes. Environmentalism is more amorphous, but one can find antecedents in medieval England and more obviously during the Industrial Revolution.
As for libertarianism, if you see it as the direct descendant of classical liberalism, then libertarians also have a more venerable lineage than conservatives. But there’s the rub. Do they? The Founding Fathers were all classical liberals, but unlike many of their opposite numbers in the French Revolution, they were largely conservative in manners, morals, and faith. Their conservatism was not labeled as such because it suffused the culture and was simply taken for granted. One need only read the writings of George Washington or John Adams to understand that they were among the first fusionists. (Robert Nisbet once hinted that even Mill, the fons et origo of so much libertarian thought, was actually more of a fusionist himself, clawing back his libertarian reductionism with caveats about the need to curb liberty for the young, the infirm, the “backward,” et al.)