The Nation has an interesting cover story this week by a young radical named Bhaskar Sunkara, an editor at In These Times and a founder of Jacobin, a new neo-Marxist magazine.

Sunkara's basic point is hard to argue with and it boils down to this: liberalism won't get far without a radical movement that presses for more fundamental change:

At the peak of the socialist movement, leftists fed off liberal victories. Radicals, in turn, have added coherence and punch to every key liberal struggle and advance of the past century. Such a mutually beneficial alliance could be in the works again.

One might add that the very existence of a worldwide socialist movement through much of the Twentieth Century deeply alarmed U.S. and other Western elites who embraced liberal welfare policies as a way to take the wind out of radical sails and "manage the poor." Norman Thomas received nearly a million votes when he ran for president in 1932. At the same time, he and other advocates of socialism could point to the industrial successes of the Soviet Union as a plausible alernative to capitalism. Overall, a vibrant radicalism made liberalism seem inherently more moderate -- the lesser of two evils on the left.

The demise of socialism globally and of American radicalism meant that liberals came to represent the far left end of the political spectrum, and helps explain the rightward shift in American politics over the past 20 years.

Without radicals pushing deeper and bolder critiques—as Occupy Wall Street did—liberalism will struggle to achieve real change and easily devolve into a technocratic project, which is pretty much where it is today, as Sunkara suggests.

Less clear, though, is just how far radicalism can get in America given this country's deeply embedded political culture. Richard Hofstadter famously said that "It has been our fate as a nation not to have ideologies but to be one." Seymour Martin Lipset once summed up that ideology with five words: "antistatism, laissez-faire, individualism, populism, and egalitarianism."

To be sure, that's a pretty conservative read of American political culture, but there is no question that class consciousness has always been very weak in America. In her extensive work on the American Dream, Jennifer Hochschild has shown how strongly Americans tend to embrace the idea that their fates are decided largely by their own individual effort as opposed to structural factors. When Americans fail or suffer economically they tend to blame themselves as opposed to blaming capitalism. The American Dream, Hochschild argues, is the dominant ideology in the United States and effectively creates a false consciousness that limits radicalism's reach here.

It is worth noting, also, that unlike nearly every other industrialized country, the United States didn't come into the modern age following hundreds of years of feudalism—which in Europe laid the basis for strong class consciousness and an us-versus-them political culture.

Yes, the socialist movement and radicalism once did have a lot of sway in the United States. But consider the circumstances of a century ago: A huge influx of European immigrants brought with them a strong class consciousness that helped greatly boost the indigenous U.S. labor movement. For instance, one of the most prominent radicals of the era, Emma Goldman, was Russian-born. Many of the leading Marxist intellectuals were Jewish children of European immigrants.

The American left remained strong into the mid-20th century amid historic conditions that were quite unique: the huge crises of the Great Depression and World War II, along with the apparent success of socialist experiments abroad. In turn, the radicalism of the 1960s reached a zenith amid some of the greatest internal conflict in America since the Civil War and the least popular foreign intervention in U.S. history.

Things may be pretty bad today, but the turbulence of the current era is nothing compared to the past. And absent far greater economic suffering or deeper instability, it's hard to see how a radical movement will overcome the American Dream ethos enough to gain anything like the power it had in previous eras. Depressingly, the financial crisis and Great Recession produced a far more powerful social movement on the right than the left.

Bhaskar Sunkara doesn't offer a plausible road to a radical revival, at least in this article. For example, he points to the Chicago Teacher's Union strike as a hopeful example and says that public sector labor unions will be crucial to future battles against austerity to preserve social goods.

In my mind, though, the centrality of public sector unions in progressive politics illustrates the problem the left faces, not the solution. Yes, these unions are important allies in various battles, but their overriding goal is—and should be—to advance the interests of their members, particularly job and pension security. As many commentators have noted, a core weakness of the left is that it has been more a collection of self-interested constituencies than a powerful social movement.

As for Sunkara's other ideas—such as centralizing more welfare functions at the federal level or defending Social Security or attacking student debt—that all sounds like the stuff we at Demos do every day.

What I want to see from thinkers like Sunkara is first, an articulation of a radical politics that is truly indigenous to American political culture and leverages core American values, such as individualism and antistatism, to its advantage—rather than running up against them as the left so often has. And second, some truly out-of-box big radical ideas that seriously challenge how liberals think about economics, culture, and politics.

Maybe all that will be in Sunkara's next Nation cover story.