Demonstrators, including supporters of the group Anonymous, in a protest against corrupt governments and corporations in front of the White House on Guy Fawkes Day, Nov. 5, 2013. It was part of the Million Mask March, with similar rallies held around the world. Saul Loeb/AFP/Getty Images

Why isn’t there a liberal tea party? Because liberals have none of the three core traits that define the tea party. They lack a hard-line ideology; they don’t have nearly as strong an infrastructure for building a successful political movement; and their party’s mainstream, instead of forming a polarized and actionable caucus in Congress, tends to ignore rather than fear the more extreme elements on its side. The tea party movement, on the other hand, has consistently pursued what Harvard law professor Mark Tushnet calls “constitutional hardball,” pushing the laws and the Republican Party to the extremes. The government shutdown in October served as a good illustration of these differences. As far-right legislators forced the rest of their party off a cliff and shut down the government, some on the left argued that liberals should have their own list of stringent demands for coming to a budget agreement, such as a public option for health care, universal preschool, and a higher minimum wage. These suggestions did not rise above irony: It was clear from the get-go that no such thing would happen. Some critics blamed this liberal impotence on the characteristics of left movements, such as the horizontal, leaderless structures of Occupy or union interests that will back the Democratic Party no matter what. Others blamed liberals for their spinelessness in standing up for their own values, resulting in a lethargic and uninterested base. But the reasons for this contrast with the tea party are actually far more structural. First, liberals and those to their left look to government to provide for the common good, and therefore have an interest in showing that the government can work well. Conservatives have their own projects for government, from mass incarceration to projecting power overseas, but when domestic government fails in the eyes of the public — be it through underfunded health exchanges or banking regulations — it serves the right politically. Such failures mean curbing the potential of the state to regulate the economy, removing long-term commitments to investing for the future, and neglecting to provide social insurance. So sabotage of governmental processes is useful in a way that it can’t be for liberals. Still, simple contempt for government doesn’t tell the whole story: Brinksmanship is evident in many minor — but important — political battles, like nominations. A look at the relative composition of both sides’ political bases offers further insight. First, the numbers. More than 40 percent of Americans describe themselves as conservative or very conservative when it comes to economic issues, according to Gallup, while barely 20 percent of Americans describe themselves as liberal or very liberal on the same issues. There are almost twice as many adults who consider themselves solidly conservative as solidly liberal. To be sure, not all of those who self-describe as conservative actually embrace a laissez-faire view of the economy. (On the contrary, many support things like Social Security, Medicare and public education but still describe themselves as conservative.) However, when it comes to pure numbers, there are many more people who side with the far right than with the far left, and this affects the popular support available for activists and voters.

Base and elites

The demographic makeup of the two sides is significant, too: The conservative base is much more homogeneous in terms of both its background and its ideology. As Ryan Lizza pointed out in The New Yorker, tea party members of the House of Representatives who forced the shutdown have constituencies that are increasingly white, thanks to gerrymandering. The places where Mitt Romney won in 2012 by large margins look more or less the same. But the United States as a whole is quickly turning into a majority-minority society. Diversity and pluralism are traits that define liberalism — so it’s no surprise that liberals represent a wider spectrum in terms of income, education, demographics and ideology. Such diversity makes clearly outlining and aggressively pursuing a unified ideological agenda difficult. For example, conservatives who are focused on lowering taxes and dismantling the federal government have relatively easy lines to draw. The task is harder for liberals. Some are committed to the idea of active government but want to see market solutions for everything and a vigorous and expansive role overseas. Others want a more social-democratic America — something closer to the governments of Western European countries — and are gravely concerned about surveillance and drone warfare. This divergence on the left makes it much harder to push through aggressive policies, and the political candidates to implement them, nationally.

Primary challenges are a way of maintaining ideological conformity, as incumbents are forced to tack rightward to fend off fresh faces.

So much for the base. What about the elites — political leaders, funders and policy wonks? Polarization in ideology is evident among them as well. Since the 1970s, an entire infrastructure of donors and policy and business interests has worked to build a proper conservative movement. Institutions that feed into the current tea party, like the Heritage Foundation, were explicitly created for this kind of mobilization. This is where primary challenges, in which ideological purists are recruited to run against moderate incumbents, become important. When you see the tea party as being composed of individuals ready to act for their cause, combined with the money and influence designed to facilitate it, direct political action becomes much easier. Primary challenges are a way of maintaining ideological conformity, as incumbents are forced to tack rightward to fend off fresh faces. This one-two punch of elite infrastructure and primary challenges simply doesn’t exist to nearly the same degree on the liberal side. The Center for American Progress (CAP), one of the Beltway’s leading progressive think tanks, doesn’t have the ability or inclination to mobilize individuals and resources to challenge moderates the way think tanks on the right do. As Julia Ioffe recently wrote in The New Republic, the Heritage Foundation has been willing to burn relationships with House Republicans to maintain outside pressure, something inconceivable for liberal organizations, much less centrist ones like the Brookings Institution, to do.

The long game