If you have been surprised by President Joe Biden’s ambitious proposals for government spending, you’re not alone. “I’ll be frank, I think a lot of us expected a lot more conservative administration,” Rep. Alexandria Ocasio-Cortez said in late April. Pramila Jayapal, Chair of the Congressional Progressive Caucus, has been similarly startled. When she heard Biden say in a televised speech, “The biggest risk is not going too big…. It’s if we go too small,” she yelled out to her husband, “That’s our line! He used our line!” For their part, Republicans have accused the president of “false advertising” for promising moderation on the campaign trail and then delivering something far bolder.

As a landmark opening move, the administration secured a $1.9 trillion economic rescue package in March. Biden’s rival in the primaries, Sen. Bernie Sanders, dubbed it “the single most significant piece of legislation for working-class people that has been passed since the 1960s.” Since then, the president has proposed some $4 trillion more in federal spending to create jobs, improve infrastructure, bolster care work and combat climate change — measures to be funded in large part by increases in corporate taxes.

Such turns, from a politician previously known for caution and bipartisanship, have led many political commentators to wonder: Who deserves credit for Biden’s newfound progressivism?

The answer to this question has been hotly debated, particularly with regard to the role of social movements. When Biden signed his initial relief bill in March, Thea Riofrancos, a professor of political science at Providence College, tweeted, “You won’t find this in the mainstream media coverage, but it’s literally impossible to imagine [this package] without the past year of organizing by Black Lives Matter, tenant orgs, DSA, Sunrise; essential workers going on strike; and the Bernie campaign.” Others, however, have doubted this proposition, arguing that Biden’s win in 2020 over more progressive candidates showed the impotence of movements and contending that the left should “dispense with the comforting illusion of having much sway.”

So how much credit do social movements actually deserve for Biden’s victories? The answer to this question is critical because it shapes the way in which we understand how change happens — and it determines whom we might look to as the potential drivers of even greater transformations in the future.

Biden’s leftward lurch — at least on selected issues — is reflective of wider changes in American politics. As Patrick Murray, the director of polling at Monmouth University, remarked in the New York Times in April, “The Democratic Party has shifted itself. It has become more progressive, and you even have centrists who are on board with a few things that they wouldn’t have been happy with a few years ago.”

This trend had become evident well before Biden took office. Indeed, even with Donald Trump still in the White House, signs had emerged that the political climate had changed, and not just among Democrats. Bitter enemies of the party’s left, such as Rahm Emanuel — former mayor of Chicago and influential advisor to the two Democratic presidents that preceded Biden — acknowledged as much. “Admittedly, today’s landscape is much friendlier for progressive ideas than it was when either Mr. Clinton or Mr. Obama was running for office,” Emanuel wrote in the Wall Street Journal in early 2020, even as he continued encouraging candidates to tack to the center. Likewise, in an October 2020 article entitled “How Democrats Won the War of Ideas,” written before Biden had even won, conservative New York Times columnist David Brooks argued, “The era of big government is here.”

“It’s not that everybody has become a Democrat,” Brooks contended, “but even many Republicans are now embracing basic Democratic assumptions.” He went on to cite the work of Charles Blahous and Robert Graboyes of the Mercatus Center, a pro-business think tank: “To show how the whole frame of debate has shifted, Blahous and Graboyes list the policies that are commonly discussed among Democrats now but that would have been too far left to get a hearing at the Democratic National Convention of 1996,” the columnist explained. “They’ve come up with many examples, including canceling college debt, more than doubling the minimum wage, shutting down coal-fired plants and guaranteeing every American a job.” Sizable portions of the Democratic delegations in both the House and Senate have signed on as co-sponsors to the Medicare for All Act. And on criminal justice issues, significant blocs of the party have embraced policies to reverse mass incarceration, with voters in several major cities electing district attorneys who directly rebuked a previous “law and order” orthodoxy. As Sanders remarked, “We have come a very, very long way in the American people now demanding legislation and concepts that just a few years ago were thought to be very radical.”

How, then, do we account for this shifting terrain?

Perhaps the most common view of how change happens assigns agency to a small number of people at the top. We are constantly schooled in a vision of history that sees presidents, generals, senators, and CEOs making consequential decisions that shape the fate of the nation. The tradition of civil resistance describes this as a “monolithic” view of power. The monolithic perspective, ubiquitous in the mainstream media, holds that if the political landscape has been altered, it is mostly because individual leaders have changed their minds. As a result of private conversions and public epiphanies, figures like Biden consult their moral compasses and decide to chart a new course. Public affairs, in turn, are reordered by their convictions.

Skepticism of this take is warranted. Of course, politicians do change their minds. But ample evidence suggests that they are more often followers than leaders — that their views typically “evolve” only after a preponderance of public opinion has already indicated that a change of heart would be conducive to their political survival. This is particularly true of Joe Biden.

As a senator, Biden was long considered a centrist Democrat who boasted of his close relationships to those as far to the right as segregationist Sen. Strom Thurmond. When it was fashionable for Democrats to show they were “tough” on criminals, Biden stepped forward to champion the 1994 Crime Bill. Later he voted for the Iraq War when a wave of post-9/11 nationalism seemed to endorse the vengeance of foreign invasion, then was compelled to acknowledge this as a “mistake” once the war grew deeply unpopular. Similarly, Biden voted for the Bill Clinton-era Defense of Marriage Act in 1996, considered widely popular at the time. And while he upstaged Obama by doubling back on his position first, he only came out in favor of same-sex marriage after that administration had already moved to stop defending the Defense of Marriage Act in court.

In a recent article for The Atlantic, writer Anand Giridharadas interviewed Jeff Connaughton, a one-time aide in Biden’s senate office who ultimately grew disillusioned with Washington politics. “You could say he doesn’t have core beliefs, that he shapes himself to the political moment,” Connaughton stated of his former boss. “He often describes himself as a ‘fingertip politician,’ that he can find the political pulse, and that pulse right now is in an exceedingly different place than it was 30 years ago.”

The charitable way to characterize such a malleable disposition, Connaughton noted, would be to say that it “shows [Biden] has the capacity for change and growth.” A less kind assessment might peg him as a rank opportunist, craven even relative to the low standard set by other career politicians. Either way, the monolithic inclination to grant politicians credit as sole actors does not provide a very satisfying explanation for why national politics have changed.

A second leading method of reckoning with a changing political landscape looks to historical conditions for explanations. Here, observers are likely to highlight the importance of sudden ruptures in the status quo (wars, financial crises, natural disasters), as well as more gradual economic, sociological and demographic developments. These conditions, they argue, are decisive in altering the behavior of political leaders.

In the current context, the COVID-19 pandemic has been the most obvious catalyst. “The pandemic has fundamentally changed a lot about the country,” White House advisor Mike Donilon told The Atlantic. “I don’t think you can go through an experience where 500,000-plus people lose their lives and everybody has their life turned upside-down and you reach unemployment levels approaching Depression-era levels and come out of that the same.” In this account, Biden sensed a national hunger for large-scale, transformative projects as a way of coming back from the malaise of lockdown and social distancing, and he responded with ambitious government action. Others have contended that disillusionment with Trumpian extremism created a window of opportunity for Biden to act, “particularly if he delivered tangible government benefits like stimulus checks and vaccines,” as the New York Times put it after the president’s first 100 days in office.

Still others have pointed to longer-term trends. Eric Levitz in New York magazine cited the idea that “America’s inequality problem became too conspicuous for even conservative-minded economists to ignore.” And elsewhere, in a two-part series in the Washington Post in late 2019, University of California-San Diego sociologist Lane Kenworthy offered a series of structural arguments to explain why the Democrats have turned more progressive since 2012. He wrote, “On cultural issues and government social programs, the United States as a whole has been moving left for decades,” for a variety of reasons: More affluent societies tend to become more tolerant and less parochial; nations generally offer more generous public benefits as their economies grow; and after popular social programs are implemented, it is hard to eliminate them.

Of course, the trends Kenworthy identifies hardly stopped Ronald Reagan from launching a far-reaching assault on the social safety net, nor did they dissuade “Third Way” Democrats like Bill Clinton from extending Reagan’s legacy and declaring “the era of big government is over.” Other structural explanations run into similar problems. There is no doubt that historical conditions play an important role in shaping political life. But whether a given event or trend will result in progress or retrenchment is rarely as clear in advance as commentators will declare in hindsight.

Naomi Klein’s influential 2007 volume, “The Shock Doctrine,” made the case that, for the previous 50 years or more, the right had successfully used moments of crisis to push forward a reactionary, pro-corporate agenda. During the Great Recession that followed the financial collapse of 2008, Barack Obama bailed out Wall Street but declined to nationalize banks, impose real accountability on financiers, or provide serious aid to homeowners facing foreclosure. In spite of then-White House chief of staff Rahm Emanuel’s recognition that “You never want a serious crisis to go to waste,” many have argued that the administration did just that. While Obama enacted a substantial stimulus package, the size and scope of the government’s response was constrained by neoliberal economic advisors such as Larry Summers — a figure whose stances promoting “balanced budgets, free trade and financial deregulation” were long regarded with great reverence in the Democratic Party. Just a few years after the 2008 crisis, the Tea Party was setting the tone in Washington, and Obama (with substantial help from then-Vice President Biden) was pursuing a “grand bargain” with Republicans to reduce the debt and scale back long-term spending on Medicare and Social Security.

Far from foretelling a transformational presidency, much conventional wisdom when Biden took his oath of office held that historical circumstances would not allow for bold action: entrenched polarization, a divided public and precarious margins in Congress would limit the administration to action that was modest at best. The fact that Biden’s moves to the contrary have been received with such surprise says much about how prevailing conditions were typically read very differently just a few months ago.

Decades after the fact, historians can always seek to identify the major structural conditions that undergirded any significant social transformation. But those trying to predict in advance how historical forces will play out have been prone to blunders. It is useful to remember that shortly before the fall of the Berlin Wall, many experts believed that geopolitics promised a period of extended continuity, with one distinguished Foreign Affairs analyst writing in 1987 that “there is no prospect of fundamental change in relations between [Warsaw Pact] countries and the USSR.”

Surely, organizers cannot afford to neglect careful examination of the social and economic factors that structure political activity. But rather than fatalistically seeing conditions as determinative, they do better to study them both for potential pitfalls and for new opportunities to advance a program of change. When a crisis hits and politicians must formulate a response, they rarely turn to ideas that are altogether novel. Rather, they draw from policies and demands that have already been put on the table. Therefore, it is important to consider how the demands get there to begin with, and to ask who sets the table.

One framework that seeks to describe how political stances once considered unacceptably fringe can drift into the mainstream is called the “Overton Window.” Originally proposed in the mid-1990s by liberatarian Joseph Overton, a staffer at a Michigan think tank called the Mackinac Center for Public Policy, the idea rapidly gained currency in the Obama era (even inspiring conservative political commentator-turned-novelist Glenn Beck to invoke it in the title of his 2010 paranoid thriller). The concept came into more mainstream usage in the run-up to the 2016 elections, when the presence of both Donald Trump and Bernie Sanders left commentators scrambling to explain why previously enshrined political norms were being wantonly defiled. By 2018, the popularity of the “Overton Window” prompted Politico to publish an article discussing “How an Obscure Conservative Theory Became the Trump Era’s Go-to Nerd Phrase.”

The basic notion is straightforward: On any given issue, political proposals can be arranged on a spectrum, with the most mainstream located toward the center and more extreme ones placed on either end. When choosing policies to support on that topic, elected officials will not look at the whole spectrum and then freely select the stances that most closely match their inner convictions. Instead, will select from a more limited set of positions — ones considered reasonably safe and “sensible.” The Overton Window describes the range of positions considered “acceptable” to politicians who want to win reelection. As the Mackinac Center explains, risk-averse lawmakers “generally only pursue policies that are widely accepted throughout society as legitimate policy options. These policies lie inside the Overton Window.” Ideas that fall outside the window are typically ignored, passed over as “radical” or “unthinkable,” even if they might have merit in addressing social problems.

While the window shows what is considered politically possible at any given time, the view it offers is not entirely fixed. On an issue-by-issue basis, the position of the window can be moved. If popular opinion changes, the window’s center may shift in either direction, redefining what passes as “mainstream” on the topic in question. And this presents an opportunity: While insider politicians and lobbyists will focus their energies on haggling over policy options within the window of “sensible” reform, outside advocates need not limit themselves to championing the most immediately pragmatic proposals. Instead, by holding up more substantive and visionary demands, they can win more in the long run by pushing the Overton Window in a direction more favorable to their politics.

Part of the framework’s appeal is that much of what it proposes makes intuitive sense. Laura Marsh, writing in the New Republic, argued that “Overton did little more than repackage the basic negotiating principle that if you ask for a lot, you will likely get more than if you ask for a little.” For their part, social movement theorists have long discussed the benefits and potential pitfalls of “radical flanks” — the argument for the upside being that the presence of militant voices for change can increase the willingness of opponents to work with more moderate reformers, who seem sensible in comparison.

When it comes to using the Overton Window as a strategy, some have interpreted the concept to suggest that it encourages groups to stake out deliberately fringe positions — going so far as to promote demands more radical than what they actually want — on the grounds that such exaggerated extremism will make the policies these groups actually desire appear more reasonable. Rachel Maddow, for one, explained the theory in these terms in an MSNBC segment. Following on this interpretation, commentators have then either endorsed such calculated extremism or, alternately, condemned it as a bad strategy.

This interpretation misses the mark. Or, at least, this is clearly not the reading supported by Overton — who died in a plane crash in 2003 — or his Mackinac Center colleagues. Their strategic intent was to argue that it is worth promoting the policies that you really want, even if these are outside of what is currently acceptable in the mainstream political debate. Although your position may have little chance of being enacted in the short term, you can have an important impact: You both move the discussion toward your desired end goal and lend immediate legitimacy to more moderate versions of your demand that might currently be on the table. As an example, if leftists promote socialized medicine, they may not win it right away, but they increase the likelihood that a “public option” for health insurance might be passed as a compromise and, over time, they also pave the way toward Medicare for All.

This is one valuable aspect of Overton Window for outsider activists: It suggests a course of action beyond “direct policy advocacy” for compromise positions that fall short of your ultimate goals. Rather, as one Mackinac document explains, advocates “should focus on educating lawmakers and the public in an attempt to change the political climate,” making longer-range ambitions more attainable. “Move the window of what is politically possible and those policies previously [considered] impractical can become the next great popular and legislative rage.”

Another strength of Overton’s analysis is its accurate view of politicians as, by and large, Machiavellian operators. Given the prevalent bias toward a monolithic view of power, it is not unusual to see pundits crediting elected officials themselves with shifting the Overton Window by staking out bold positions. However, this is a misreading of the original theory, which saw elected officials responding to changes in the electorate that were not of their own making. As Mackinac President Joseph Lehman writes, “Many believe that politicians move the window, but that’s actually rare. In our understanding, politicians typically don’t determine what is politically acceptable; more often they react to it and validate it. Generally speaking, policy change follows political change, which itself follows social change. The most durable policy changes are those that are undergirded by strong social movements.”

Trump, in particular, was commonly said to have “smashed” the window open, and Sanders has also been mentioned frequently as an Overton Window-breaker. To be fair, insurgent candidates are far more likely to move the window themselves than are more mainstream politicians. But such renegade candidates, many of whom are connected to social movements, are exceptions to the rule. When politicians do push outside accepted boundaries, they usually pay a price for it. Those trying to build lasting careers and gain standing within the establishment are generally unwilling to take such risks.

Being center-right libertarians, the Overton Window’s originators took their view of politicians as being self-interested and pliable from the field of public choice economics. But it hardly takes any theory at all to detect careerism and other unflattering motives at work in the behavior of officials who enter the proverbial “swamp” of mainstream politics. Rather than politicians setting the course for social change, the Mackinac Center argues, “it’s the rest of us who ultimately determine the types of policies they’ll get behind…. [O]ur social institutions — families, workplaces, friends, media, churches, voluntary associations, think tanks, schools, charities, and many other phenomena that establish and reinforce societal norms — are more important to shaping our politics than we typically credit them for.” In other words, it is the movement of public opinion, and how this change is embedded in such pillars of society over time, that leads politicians to evolve in their thinking.

Using this framework as a guide, one can find solid rationale for believing that social movements had a significant role in pushing the spectrum of policy on key issues. In doing so, they both contributed to the leftward migration of the Democratic Party and set the stage for Biden’s bold proposals for government spending.

As one example, by putting the Green New Deal on the map, groups like the Sunrise movement have fundamentally reoriented the policy conversation around climate change and created a new standard by which Democratic candidates have been judged in the past two years. An analysis by the progressive think tank Data for Progress determined in late 2019 that Biden’s climate plan was more comprehensive than Bernie Sanders’s had been in 2016 — reflecting a sea change in the debate that happened well before the COVID-19 pandemic hit. Nevertheless, early in the primaries, environmentalists slammed Biden’s plan as far inferior to those that his competitors had embraced. This ultimately compelled Biden to make more far-reaching commitments, which have now been at least partially incorporated into his infrastructure plan.

Famed linguist and political analyst Noam Chomsky told The Atlantic that the revised climate proposal was “far better than anything that preceded it. Not because Biden had a personal conversion or the DNC had some great insight, but because they’re being hammered on by activists.” This assessment of Biden’s motives was shared by the Trump campaign, which dubbed the former vice president a “puppet” of left-wing extremists. Although Chomsky quipped that Biden’s final plan was “largely written by the Sunrise Movement,” the group exercised influence much less through direct input offered in venues such as the Climate Engagement Advisory Council than through moving the goalposts in the public debate.

As another example, in the Obama years it took the Occupy movement to shift the focus away from austerity and a Tea-Party inspired “grand bargain,” and to instead rally public sentiment in favor of measures to combat inequality, tax the wealthy and fund social programs. This message was then greatly amplified by the insurgent political campaign of Sanders in 2016, and later by Ocasio-Cortez and other members of “the Squad.”

More than most politicians, Sanders was able to reposition the window of possibility due to the nature of his campaign — which sought to eschew big-money donors and other conventional sources of legitimacy and instead forge new electoral coalitions. In the case of the 2016 presidential cycle, his unexpectedly strong showing led Hillary Clinton to adopt flattering forms of imitation, taking notable progessive turns on issues ranging from health care to trade to college tuition. Suggesting that Sanders might lose the primary but win the war, Bob Cesca wrote in Salon that “the best indicator of [the Overton Window’s] leftward voyage has been Hillary Clinton’s cleverly perceptive adaptation of Bernie’s positions” — a trend later parodied in a Saturday Night Live sketch that showed Clinton desperately trying to look cool to millennials by not only borrowing Bernie’s policy proposals, but also stealing his Brooklyn accent and rumpled wardrobe.

Drives by Sanders and members of the Squad have gone far in legitimizing once-taboo positions. But they have perhaps been equally effective in demonstrating that many ideas previously considered politically out of bounds were actually widely popular. As the New York Times reported in early 2019, “Polls show that some support crosses the partisan divide. Forty-five percent of Republicans in one poll supported Representative Alexandria Ocasio-Cortez’s suggestion to tax income over $10 million at 70 percent; among all American adults, 59 percent supported that.” This can be seen as an example of non-electoral organizing and movement-identified campaigns creating a mutually reinforcing cycle with the power to alter the political climate.

The Overton Window is helpful in explaining such trends. Yet the problem with the framework is that it fails to reckon with power. There are many political ideas that enjoy widespread public support but have nevertheless perennially failed to become law. The policies that are actually enacted are overwhelming ones backed by power. This — in the words of a classic Alinskyite maxim — takes the form of either organized money or organized people.

The issue of gun control provides a textbook case in point. Consistent majorities of the American public have expressed support for stricter gun laws, with reformers promoting exceedingly moderate “common-sense” measures, such as assault weapon bans and expanded background checks. And yet these advocates have made scant progress at the federal level in recent decades. The reason is that their opponents are able both to rally a passionate base of active supporters and draw from a heavy war chest of resources in defense of the pro-gun cause. Except during rare periods of anti-gun mobilization, such as in the wake of the Parkland shooting, support for reform has been broad but inadequately deep. As a result, gun-control advocates have been limited to modest changes, and only at the state and local levels.

Those who originated the Overton Window saw their role as supplying lawmakers with policy ideas and doing some amount of public education. However, from their think-tank offices, they could not conceive of any actual organizing program. They took inspiration from market-fundamentalist guru Milton Friedman, who wrote: “That, I believe, is our basic function: to develop alternatives to existing policies, to keep them alive and available until the politically impossible becomes politically inevitable.” While such a mission is not entirely unfounded, it shows little awareness of what social movements do. By moving the spectrum of support, they not only turn people undecided about an issue into latent allies, but they radicalize and activate people who were already sympathizers, turning previously passive backers into dedicated adherents. When these energized supporters invest their time, passion, and resources in the fight, they generate power.

In a highly polarized political context, the window of possibility has not moved so much as it has expanded. Diametrically opposed policies are being placed on the table at the same time. “Instead of a consensus edging one way or another, we have a choice between two poles,” argues Laura Marsh. Here, social movements are likely even more important than the Overton framework would suggest, for a simple reason: They are at the heart of efforts to create bases of people actively committed to strengthening the correct pole and persuading others to join them.

Ultimately, the exact combination of factors that moved Biden to action cannot be known, and it is not necessary to deny that personal convictions and historical conditions have played a role in Washington’s shifts. But the factor that likely has the most significant impact is also the one that is the most neglected in media, denied by insider operatives, and misunderstood by the public. “[Y]ou can’t look at Biden or Obama without looking into the moment in which they are living,” Sanders argued in a recent interview. Ironically, as a candidate who has done the most to shift the Overton Window himself, Bernie is one of the politicians who has worked hardest to dispel the myth of monolithic power. “[I]n the last number of years…” he argues, “political consciousness in this country has changed,” something he attributes to the progressive movement’s elevation of social and economic issues.

Biden, in the words of one New York Times headline, was “No One’s Idea of a Historic Figure.” Rather, he was known for reading the political signs of the times. His bold push into progressive policymaking on government spending has required him to step away from his preferences for bipartisanship and to break with a track record of moderation. Some may conclude that his personal convictions or the unique moment created by the pandemic alone were sufficient to prod him down this path. Those who wish to see the president stay on this course have good reason to believe otherwise, and to organize accordingly.