Imagine a foreign visitor who has learned just one fact about America: For the past century our politics has been defined by a contest between two movements, one intermittently calling itself “progressive” and the other more consistently calling itself “conservative.” He would rightly conclude from those labels that partisans of the two movements agree that the arc of history bends toward progressivism and away from conservatism. Progressives, that is, believe they have history’s wind in their sails. They constitute, in that sense, the party of the future. Conservatives, on the other hand, are committed to the stewardship and transmission of a legacy that is both vulnerable, thereby requiring conservation, and valuable, thereby deserving it. Conservatives thus constitute the party of the past.

Progressives are animated, in the late Richard Rorty’s words, by “the hope that life will eventually be freer, less cruel, more leisured, richer in goods and experiences, not just for our descendants but for everyone’s descendants.” Progressives of a century ago believed that progress meant movement toward a known destination, and that the ways to effect it were demonstrable. In the 1930s, around the time they began calling themselves “liberals,” progressives abandoned the conceit that social sciences could, in Condorcet’s phrase, “foresee the progress of humankind, direct it, and accelerate it” in the way the natural sciences understand physical laws and thereby direct and accelerate material progress. But their optimism is undiminished. They continue to believe in “the evolving standards of decency that mark the progress of a maturing society,” as Chief Justice Earl Warren wrote in a 1958 Supreme Court opinion, even if they deny the possibility of formulating criteria whereby we could know that our standards are improving, not just changing.

Conservatism, by contrast, lends itself to wariness. Samuel Johnson’s rule that “men more frequently require to be reminded than informed” comports with the conservative inclination to believe that old wisdom is plentiful while new wisdom is scarce and suspect. What disheartens is the need to remind the same people of the same things, over and over, entreating them not to squander legacies hard won and repeatedly vindicated. Thomas Sowell once wrote that much of modern social history “has involved replacing what worked with what sounded good.” Or, as William F. Buckley Jr. lamented in National Review’s first issue in 1955: “Instead of covetously consolidating its premises, the United States seems tormented by its tradition of fixed postulates having to do with the meaning of existence, with the relationship of the state to the individual, of the individual to his neighbor, so clearly enunciated in the enabling documents of our Republic.”

In the same publisher’s statement, Buckley famously declared that National Review “stands athwart history, yelling Stop.” He remarked further on the challenge of living in “a world dominated by the jubilant single-mindedness of the practicing Communist, with his inside track to History.” A third of a century later that track turned out to lead to the collapse of one of the hardest despotisms human beings have ever endured. Sometimes if you yell “Stop,” history obeys.

And sometimes it doesn’t. The issue of National Review published immediately after the 2012 election declared that contest to have been a “terrible defeat,” “debacle,” and “catastrophe” for conservatism. In a world where Soviet Communism has been consigned to the dustbin of history, such judgments might sound excessive. Since the end of the Cold War, conservatives have warned against the “Swedenization” of America. These warnings are, most directly, about a policy regime wherein government spending accounts for more than half of gross domestic product and government regulation is the biggest factor affecting the generation of the rest.Data from the Organisation for Economic Co-operation and Development show that, in 2010, all government spending in Sweden equaled 53 percent of GDP. The same figure was 55 percent in Finland, 56 percent in France, and 58 percent in Denmark. Sweden’s comparative austerity suggests that vigilance against the “Denmarkation of America” would be more apposite. Federal-, state-, and local-government expenditures in 2010 amounted to 42 percent of America’s GDP, which means that we’re behind Europe, but not that far behind. Moreover, we’re catching up: In 2000, government spending in the U.S. accounted for 34 percent of GDP.

Well, what are a few percentage points of GDP among friends? By this rudimentary measure of government outlays as a proportion of national income, America already differs from Scandinavia in degree rather than in kind. If conservatives want to avert the Swedenization of America, they need to explain, more comprehensively than they have done so far, the deplorability of that outcome, since Western European social democracy appears benign where Eastern European Communism was manifestly grotesque.