Reuters

In a classroom in Harlem, the liberal new mayor of New York, Bill de Blasio, appeared with union leaders in support of his plan to raise taxes on incomes higher than $500,000 to fund public pre-kindergarten. “We’re asking this of the wealthy,” de Blasio said, “because there are too many working parents in this city today” who need help.

At the same time, New York Governor Andrew Cuomo was presenting his budget in Albany under a sign that trumpeted: “CUTTING TAXES.”

You could hardly get a better illustration of the current tribal divide in the Democratic Party. Call it what you want—liberals versus centrists, populists versus the corporate wing—but these days, there’s no doubt there are two different breeds of Democrats, both in elected office and in the activist grassroots. Along with Massachusetts Senator Elizabeth Warren, de Blasio has been hyped as the avatar of a new, more boldly progressive Democratic Party that discards the timid moderation advocated by the party’s old guard in favor of a frank, take-no-prisoners crusade for higher taxes and bigger government.

But do Warren and de Blasio really represent the party’s mainstream? The Democrats’ liberal faction has been greatly overestimated by pundits who mistake noisiness for clout or assume that the left functions like the right. In fact, liberals hold nowhere near the power in the Democratic Party that conservatives hold in the Republican Party. And while they may well be gaining, they’re still far from being in charge.

The misimpression that the liberals have taken the reins of the party has become widespread. To take just one representative example: “The mainstream of the party has now veered back toward its more populist and pacifist instincts,” Yahoo News‘ Matt Bai wrote Thursday, characterized by “outright contempt for the wealthy and for conservatives generally.” Like others who embrace this analysis, Bai draws the conclusion that this will be an obstacle to the presidential prospects of Hillary Clinton, who is perceived as hawkish, establishmentarian, and friendly to corporate interests.

Many Democratic insiders minimize the party’s divide. They note that there’s broad ideological agreement on social and cultural issues, from abortion and gay marriage to gun control and immigration. National-security and foreign-policy questions have the power to divide but are no longer litmus tests. Even on economic issues, the party generally speaks with one voice: in favor of universal healthcare, against reducing safety-net programs, for progressive taxation and government-driven economic stimulus. Neera Tanden, president of the Center for American Progress, told me in an email that the Democratic Party just doesn’t get hung up on internecine battles these days. “I believe that it’s a big-tent party that can and should accommodate centrists and liberals,” Tanden said. “That ideological purity has not been a winning strategy for the other side.”

But this high-altitude view elides real differences, such as disagreement over how much to raise taxes and on whom, how much to regulate industry, and whether to press not just to preserve but to expand those safety-net programs. (In addition to the Cuomo-de Blasio feud, Warren’s signature proposal would increase Social Security benefits, and Obama’s push for new free-trade agreements has run into resistance from Senate Majority Leader Harry Reid.) And the divide isn’t so much about issues as tone and tactics. The Warrenites harp on the gap between rich and poor and inveigh against big business; the centrists assure their big corporate donors that Democrats can be business-friendly.

The comparison to Republicans is inevitable and instructive. No one seriously doubts anymore that the GOP is badly divided, with a right-wing faction that has virtually declared war on the more moderate establishment. But few of the party’s politicians disagree on social or cultural issues (immigration is a notable exception), and the view that taxes should be lower and government smaller is virtually unanimous. What the Ted Cruz faction and the John Boehner faction disagree on is whether the party’s rhetoric ought to be conciliatory or scorched-earth, and how far to go—shutting down the government? refusing to raise the debt ceiling?—in pursuit of agreed-upon goals like getting rid of Obamacare. The GOP’s divide, like the Democrats’, is more about tone than about issues.

But the Republican analogy becomes misleading when pundits assume that liberals play the same role in the Democratic Party that conservatives do in the GOP. The fact is, the parties are asymmetrical. There are a lot more conservatives than liberals in America. Almost all Republicans consider themselves conservative, whereas less than half of Democrats consider themselves liberal. These two charts from Gallup tell the story:

An overwhelming 70 percent of Republicans are conservatives, a share that has increased since 2000. This fits with the conventional wisdom of a GOP that’s steadily become more ideologically pure and less moderate. Meanwhile, just 43 percent of Democrats call themselves liberal. Until 2007, liberals weren’t even a plurality of Democrats—more were moderates—and even today, liberals are outnumbered by moderate and conservative Democrats. Note that there are about four times as many conservative Democrats as liberal Republicans. Liberals are increasing—their overall share of the American electorate this year, 23 percent, marked an all-time high in Gallup’s polling—but there’s a clear imbalance in the way the two parties are ideologically composed.

This imbalance is also readily apparent in the political contests where it’s been tested. The right has proved its sway over the GOP time and time again. The Tea Party has had notable success taking out establishment Republicans in party primaries, from venerable incumbents like Bob Bennett and Dick Lugar to the establishment-anointed candidates rejected by primary voters who preferred Rand Paul, Ted Cruz, Marco Rubio, Sharron Angle, and Christine O’Donnell. Even before there was a Tea Party, “RINO,” for “Republican In Name Only,” was a poisonous label in GOP politics.

Activists on the left have periodically tried to stage these sorts of purifying contests, but they have rarely succeeded. Howard Dean’s “Democratic wing of the Democratic Party” proved less potent than John Kerry’s mainstream appeal in 2004. The populist Democrat of 2008, John Edwards, also didn’t become the party’s standard-bearer. Also in 2008, in the sixth most Democratic state in the country, Delaware’s state treasurer, Jack Markell, ran for governor as a centrist against a liberal lieutenant governor who was endorsed by the state Democratic Party; Markell won. In 2010, liberals and unions teamed up in a massive effort to defeat conservative Democratic Senator Blanche Lincoln in a Democratic primary in Arkansas; they spent millions of dollars boosting Bill Halter—and lost. That year also saw a tough Democratic primary between appointed Senator Michael Bennet, a centrist former education-reform-boosting school superintendent, and a liberal state lawmaker backed by the teachers union; Bennet prevailed. (Disclosure: Bennet is the brother of Atlantic editor in chief James Bennet.) Of five candidates endorsed in 2012 congressional primaries by the Progressive Change Campaign Committee, four lost.

Compared to Republicans, Democrats are relatively free to antagonize their ideological core supporters.Liberals’ one Tea Party-style coup in recent years was the 2006 Connecticut Senate primary, in which millionaire telecom executive Ned Lamont defeated pro-Iraq War Senator Joe Lieberman. Lieberman, however, went on to win the general election as an independent. (The largely bygone Democratic split over Iraq was also distinct from the current fracture over economics.) Lamont, by the way, tried again: He ran for Connecticut governor in 2010 and lost the Democratic primary.

This dynamic means that compared to Republicans, Democrats are relatively free to antagonize their ideological core supporters. After 34 House Democrats voted against healthcare reform in 2010, progressives vowed revenge, but all 30 anti-Obamacare Democrats who sought reelection won their primaries. Conservative Democrats like former Senators Ben Nelson and Max Baucus drove liberals crazy, but they never faced a primary challenge. The architects of the Democrats’ House and Senate electoral strategies, former Representative Rahm Emanuel and Senator Chuck Schumer, built Democratic majorities by recruiting business-friendly centrists to run—and the party bosses hardly ever had a problem getting their favored candidates safely through to the nomination.

It’s telling that the many articles about a new explosion of Democratic liberalism generally cite just two examples: Warren and de Blasio. De Blasio made it through a tough primary on an unambiguous populist platform; Warren was unopposed for the Democratic nomination. Both hail from some of the most Democratic areas in the country. They could be a harbinger of the party’s future—or they could be exceptions that prove the old rule. In addition, Obama is sometimes cited as striking a more populist tone, but this is highly debatable. It’s been more than two years since the much-vaunted economic speech in Osawatomie, Kansas, that supposedly signaled his turn in this direction. That’s hardly a new tack—and it matched much of his rhetoric going back to 2007.

Many progressives acknowledge that they’re not the dominant force in the Democratic Party. But they argue that their influence is increasing. Dan Cantor, executive director of the Working Families Party, a New York-based liberal coalition that backed de Blasio and is beginning to expand into other states, told me he sensed “a lot of energy” for the fight against inequality, but admitted the upper hand still belongs to the “dead-centrists.” The party’s corporate wing retains control because it has the money, he said. “Inside the Democratic Party, we’re not quite as powerful as the Tea Party inside the Republican Party, but that’s the ambition,” Cantor said.

“I would put it this way: In the battle between the Elizabeth Warren populist wing of the party and the corporate wing of the party, the Elizabeth Warren wing is clearly ascendant,” said Adam Green, one of the founders of the Progressive Change Campaign Committee. The group’s name is a play on the Democratic Congressional Campaign Committee, the party’s House electoral arm, and it was founded to function as an alternative to Emanuel’s centrist candidates. But Green denies the group is focused on winning primaries and argues it has succeeded at changing what Democratic candidates talk about.

Many progressives acknowledge that they’re not the dominant force in the Democratic Party. But they argue that their influence is increasing.

When the PCCC endorses an underdog primary candidate, he said, the establishment candidate usually rushes to rebrand herself as “progressive,” a sign that that’s what Democratic primary voters respond to. “On the one hand, that’s less satisfying than a genuine progressive winning, but it shows that, in primaries, being progressive matters,” Green told me. In a recent special congressional election in Massachusetts, the PCCC hosted its first-ever debate, and all five candidates attended and voiced support for liberal positions. The PCCC’s preferred candidate, Carl Sciortino, was defeated by a blitz of ads that showed the winner, Katherine Clark, side by side with Warren. Even Blanche Lincoln, under pressure from Halter, tacked to the left, successfully championing regulation of derivatives in the Dodd-Frank Wall Street reform bill.

In the decade since Dean rose as the left’s champion,  the Democratic Party has moved substantially to the left, argued Markos Moulitsas, the founder of the influential site Daily Kos.”On everything from economic populism to marriage equality to gun control, the Democratic Party has evolved in the right direction,” he told me in an email. The party has also become more dependent on small donors relative to corporate ones, he said, making it “a party that is far more responsive to its grassroots than it has ever been before,” Moulitsas said.

The real answer to the question of who is in charge of the Democratic Party, Moulitsas said, is “the president of the United States.” The question of where to put Obama on the liberal-to-centrist scale haunts any debate about the modern Democratic Party. Even as his opponents brand him a socialist, Obama’s administration has disdained what former Press Secretary Robert Gibbs termed the “professional left.” One attempt to evaluate the question empiricallyfound him to be more liberal than Senate Democrats, but less liberal than Bill Clinton, Jimmy Carter, or John F. Kennedy. Obama has often seemed torn between a liberal philosophy and a desire to split differences. He approved healthcare reform with no public option, a Wall Street-reform bill the left saw as inadequate, and a succession of budget deals progressives have decried. Rather than talk about income inequality, he focused his latest State of the Union address on “opportunity,” a highly significant tweak of verbiage. Since the Democratic wars of the Clinton era, these buzzwords have been dog whistles for the party’s liberal and centrist factions.

It’s often speculated why there isn’t a Tea Party of the left. Many expected the Occupy movement to manifest as the Democrats’ Tea Party, then were mystified when it didn’t happen. Progressives are right that their stock is rising, and they’ve gained some influential champions in recent years. But don’t overestimate their power: Their clout in the Democratic Party is still limited. In other words, President Elizabeth Warren may have to wait.