Conservatism: a political or theological orientation advocating the preservation of the best in society and opposing radical changes.
Liberalism: a political orientation that favors social progress by reform and by changing laws rather than by revolution.
Ian Welsh observes in a comment that “those definitions are not how those who claim to be either liberals or conservatives operate or have operated in living memory in the United States,” and he makes a good point. Being in a comment rather than in an original post, he does not go onto as much depth or explain his point as cogently as his writing usually does.
Those who call themselves conservatives today are actually reactionaries. They do not seek to maintain “the best in current society,” but rather to unwind existing programs in order to return to a “better” past. The Luddites were also reactionaries, who wanted to dismantle the Industrial Revolution in order to return to the simpler pastoral life that had preceded it.
And, by the way, the “better past” touted by today’s “conservatives” was by no means the rosy state of affairs that they portray. Life was “ugly, brutish and short” and the oligarchs controlled things even more then than they do now. Which may be their point and their objective, but…
Those who call themselves progressives do nothing more than argue for the preservation of programs which were in place before their parents were born in many cases, Social Security and Medicare, and lobby for the continuance of “New Deal” type of spending that has been the practice for even longer. This is the very definition of conservatism.
Even Paul Krugman, the doyen of “liberalism,” illustrates today his true conservatism as he writes that, “Many of us wish that Obamacare were a simpler system, one that directly provided health insurance.” Emphasis added by me. The true liberal would have written that as, “…one that directly provided health care.”
And, yes, please don’t cite “health care reform” as an example of today's Democratic Party progressivism. Making health insurance mandatory instead of optional is not progressive.
So for all practical purposes we have no liberals today; instead we have conservatives and we have reactionaries, both using aliases.