Many activists and writers on the Left welcomed Vermont Sen. Bernie Sanders’s announcement that he would challenge former Secretary of State Hillary Clinton for the 2016 Democratic presidential nomination.

The April 30 declaration of a number of Occupy activists and others, calling themselves People for Bernie, was emblematic:

We are activists and organizers trying to build a broad, effective movement for democratic change . . . To that end, we support Bernie Sanders in his bid to become the presidential nominee of the Democratic Party. We stand firmly behind Senator Sanders as the strongest progressive possibility in the race right now. His commitment to our values is one of long-standing commitment.

The Progressive Democrats of America (PDA) had mounted an online petition calling on Sanders to run in the Democratic presidential primary, on the grounds that “we all need a ‘fighter’ to stand up on behalf of a fair economy that works for all of us, just as Bernie Sanders has done throughout his entire career.”

Echoing the message from the Nation magazine, the PDA argues that Democratic voters “would all benefit from a serious primary challenge based on policy substance and real issues rather than trivial personality differences.”

Crucially, the PDA reaffirmed the importance of Sanders’s campaign taking place inside the Democratic Party primaries: “Sanders understood the very real danger of total Republican control of the US government in 2004, including the then-impending danger of George W. Bush appointments to the Supreme Court, when he supported Democratic nominee John Kerry for President over his long-time friend and ally, Ralph Nader.”

Another pro-Sanders perspective came from Jacobin editor Bhaskar Sunkara. This one was less focused on Sanders himself or his campaigns’ supposed benefits to the Democratic primaries, but on the potential for the Sanders campaign to “build organization and pressure from the left.” Citing the example of the Tea Party’s influence in Republican Party politics, Sunkara proposed that a Sanders run can:

solidify progressives into a coherent voting bloc . . . [S]een as an opportunity for movement building, Sanders’s candidacy could strengthen the left in the long run. The tensions among Democrats are serious and raise the possibility for the realignment of progressive forces on a totally different basis.

Sunkara also asserts that Sanders’s identification with the “socialist” label can help socialists organize and bring their ideas to a national audience: “When [Sanders] fails [to win the Democratic nomination], there’s every reason to believe that radical voices can take his place, carrying the memory of [Eugene] Debs back into the political mainstream.”

The various pro-Sanders positions among these leftists have different shades of emphasis. For example, People for Bernie sounds as if they believe Sanders could actually win the Democratic nomination — a far-fetched proposition even if the frontrunner and presumed nominee Hillary Clinton stumbles in some profound way. The PDA petition, on the other hand, is clearly calling for Sanders to run a vigorous campaign for second place.

Both these appeals hang their hopes on Sanders raising progressive demands in society at large, but especially within the Democratic Party. Sunkara’s position seems to be less focused on Sanders or the Democratic Party, and more on the potential for the Sanders candidacy to help the Left and socialists organize something outside the Democratic Party.

Despite their differences in emphasis, however, each of these appeals for Sanders accept an analysis that the Democratic Party is divided between a “centrist” and a “progressive” wing — and that an underdog national campaign by a genuine liberal can either force the Democrats to commit themselves to more progressive policies, force open the internal party rift and shake up the stagnant US mainstream political scene, or both.

The history of the Democratic Party and its long list of progressive underdogs tells us something different. The reason the party remains firmly in the grip of neoliberalism today is, in part, because these liberal challenges were less successful than their supporters hoped they would be. So the question is: why will Sanders be any different?

While there certainly are real disagreements between the mainstream neoliberals and more traditional liberals of the Democratic Party, that doesn’t mean there’s a fundamental divide within the party. Indeed, the rise of “the new new left” of progressive Democrats celebrated a couple years ago has turned out to be more of a mirage.

But even if we set aside the weaknesses of the party’s liberal figures and accept the characterization of a two-winged Democratic Party, no one could deny that the tensions are a far cry from a couple generations ago, when the Democrats were much more fundamentally rent by the two burning questions of the 1960s and ’70s: civil rights and the Vietnam War.

So how did the liberals do then?

A landslide victory for the Democrats in 1964 — when the civil rights movement was in full swing — gave President Lyndon Johnson the huge congressional majorities that he used to push through a series of reforms, such as Medicare and Medicaid and various “war on poverty” programs, over the next two years.

At the same time, however, Johnson was committed to escalating the Vietnam War, with the support of a majority of Democrats. By 1966, LBJ was raiding the budgets of the war on poverty to fight the war in Vietnam.

The Vietnam-fueled spending binge pushed an overheated economy into an inflationary spiral. The ruling-class consensus that had underpinned the “welfare-warfare” state began to splinter. By 1968, it was clear even to Wall Street that the Vietnam War was “unwinnable” and was causing major damage to the US economy. Johnson’s hope that the Great Society would buy allegiance from the poor blew up in his face. Instead, he faced disintegration in the US Army, insurrectionary riots in all of the country’s major cities, and widespread protest against the war in Vietnam.

One reflection of this discontent was the announcement in November 1967 by Minnesota Sen. Eugene McCarthy that he would challenge Johnson for the Democratic presidential nomination in 1968. McCarthy was a quirky, but relatively mainstream, liberal who called for a negotiated settlement to the war. Certainly, he was no radical — his main appeal was that he wanted to “restore belief in the American political process” among those who “make threats to support third parties or other irregular political movements.”

To much of the antiwar movement — especially those newly won to opposing Vietnam — McCarthy’s candidacy seemed to transform the situation. Thousands of young activists went “clean for Gene” — cutting their hair and putting on suits, ties and skirts — to canvass for McCarthy during the primary elections in 1968.

The Vietnamese uprising in the Tet Offensive at the end of January 1968 demonstrated to the world that the US was actually losing the war — contrary to all the propaganda coming from the White House and Pentagon. This massive shift of opinion against the war had its echo in the first primary vote in New Hampshire in March, where McCarthy took 42 percent of the vote. Within a few days, LBJ dropped out, saying he wouldn’t seek another term in the White House.

Throughout the Democratic primaries in 1968, voters consistently backed candidates who promised to wind down the war — from McCarthy; to New York Sen. Robert Kennedy, who was assassinated after winning the California primary in June; to South Dakota Sen. George McGovern. But at the Democratic convention in Chicago, the party bosses imposed Hubert Humphrey, LBJ’s pro-war vice president, as the nominee.

To antiwar activists and delegates representing McCarthy and the others, the Democratic establishment offered nothing at all. In fact, Chicago Mayor Richard Daley turned the city into an armed camp, unleashing his police force on protesters in the streets near convention hotels. The images of police beating hundreds of demonstrators were so shocking that Connecticut Sen. Abraham Ribicoff, a McGovern delegate, denounced them as “Gestapo tactics” on the floor of the convention.

In November — just four years after LBJ had won a landslide victory — conservative Republican Richard Nixon defeated the divided “majority” party with a mere 43 percent of the popular vote. The Democratic Party’s actions in Chicago and its refusal to address the concerns of its grassroots supporters — as well as international events like the May general strike in France and the Russian invasion of Czechoslovakia “turned a generation of radical activists into revolutionaries,” Joe Allen writes in Vietnam: The (Last) War the U.S. Lost.

What, if anything, does McCarthy’s campaign for the White House tell us about Sanders today? That thousands of activists drew radical conclusions, despite the ultimate failure of McCarthy’s campaign, would seem to support the idea that a similar effort could lay the groundwork for greater organization of the Left. But a closer look shows the opposite.

First, as important as movements like Occupy Wall Street or Black Lives Matter are, they are nowhere near as widespread or powerful as the antiwar or Black Power movements of 1968 were. Whatever impact McCarthy’s campaign had inside the Democratic Party owed to what was going on outside the party, not the revolt within it.

Sanders’ supporters today have even less ambition than 1968’s McCarthy supporters, who were challenging the central plank of the foreign policy agenda of a sitting president. And even if thousands of antiwar activists drew radical conclusions from their failed efforts to influence the Democratic Party from within, that was certainly not the intention of those who went “clean for Gene.”

In considering Sunkara’s argument about the Sanders campaign, one has to ask, why should the Left advocate for thousands of activists to spend the better part of a year on an effort that nearly everyone agrees is doomed from the start in order to end up with a more radical remnant? Wouldn’t it be better to organize those activists for political independence from the capitalist parties now?

The pig-headedness of the barons of the Democratic Party in 1968 helped create a generation of activists who spoke of “new politics” and radical change. But — and we should keep this in mind when we hear about the potential for a Sanders campaign to create an independent force for change — it’s likely that many thousands more people moved from the McCarthy campaign into the Democratic Party.

That’s because leaders of the Democrats realized that they had to adapt to the political climate by providing the appearance of more openness to young people, women, and people of color.

An internal party commission, led by McGovern and Minnesota Rep. Donald Fraser, convinced the Democratic leadership to change delegation selection and convention rules for the 1972 presidential election. These rule changes diluted the power of party bosses and increased representation of youth, women and people of color.

The results proved very effective for McGovern, who locked up most of the votes he needed to win the presidential nomination before the 1972 convention. The outward appearance of his coalition of supporters — young, multiracial, antiwar, even “hip” — made it seem as if the “Left” really had a chance to take over the Democratic Party.

In reality, McGovern had the backing of a segment of business executives, including cosmetics boss Max Factor III and the CEOs of Xerox and Continental Grain. His campaign pursued a conscious strategy of “co-opting the Left,” in the words of McGovern campaign manager Gary Hart, by recruiting antiwar activists to participate.

But the bulk of US business wasn’t willing to follow the McGovern backers. Neither were the powerful forces inside the Democratic Party that had become accustomed to playing their assigned roles in the setup of Cold War liberalism. The State Department had long before corrupted the AFL-CIO, funneling millions in government money toward building anticommunist unions and parties throughout the less developed world — thus, the mainstream labor movement refused to back McGovern.

By effectively — and sometimes openly — abandoning the liberal McGovern, these sections of the Democratic establishment contributed to his landslide defeat in 1972 against incumbent Richard Nixon.

Even so, the McGovern campaign proved to be a watershed for the regeneration of the Democratic Party over the next generation. Gary Hart went on to become a senator and future presidential candidate himself. Bill Clinton and his future wife, Hillary Rodham, managed McGovern’s campaign in Texas. Sections of the National Women’s Political Caucus (NWPC), formed in 1971 by prominent feminists such as Gloria Steinem and Betty Friedan to push for passage of the Equal Rights Amendment and abortion rights, became key McGovern supporters.

Also in 1972, more than eight thousand black activists participated in the National Black Political Convention in Gary, Indiana, to consider a black political agenda that would include independence from the two corporate parties. But Rev. Jesse Jackson, who played a key role in opposing a break from the two-party system at that convention, joined up with McGovern’s 1972 Democratic presidential campaign afterward.

That year may have marked Jackson’s most prominent initial foray into Democratic Party politics, but his presidential runs in the 1980s are the most important to consider as historical precedents for Sanders’s campaign today.

Many sincere activists and antiracists looking for a way to respond to Ronald Reagan’s right-wing policies in the 1980s were drawn to Jackson’s 1984 and 1988 presidential campaigns, as well as “insurgent” local campaigns, such as the one that elected Harold Washington as Chicago’s first African-American mayor in 1983.

Sheila Collins, author of The Rainbow Challenge, argued that the National Rainbow Coalition (NRC) represented a solution to the failure of the 1960s civil rights and Black Power movements to consolidate their gains because of “the separation of the social movements from electoral politics.” Others argued that the Rainbow Coalition assembled a “coalition of the rejected” that, if mobilized in the electoral arena, would push American politics to the left. Still others claimed that the Rainbow Coalition offered a way to reinvigorate the movements of the 1960s.

To many Rainbow supporters, the NRC’s electoralism was seen as secondary to its potential as a “political movement,” a description in the NRC’s founding document, which appeared to reach beyond electoral politics. Rainbow politicians’ electoral ambitions were seen as secondary to the “mass movement,” which would provide the push for real reform struggles. Plus, Rainbow supporters argued, activists could use Jackson’s rhetoric and his access to the media to build grassroots struggles, like the movement in solidarity with the struggle against apartheid in South Africa.

The 1984 Jackson campaign won about 21 percent of the vote in the Democratic primaries, including outright victories in several key Southern states. Nevertheless, the party’s rules limited Jackson’s showing at the convention to only 11 percent of delegates.

With an overwhelming advantage achieved well before the convention, former Vice President Walter Mondale won an endorsement from Jackson without conceding anything. Mondale dismissed all of the Rainbow Coalition’s platform proposals — which, in fact, included only two of the seven proposals comprising a minimum black political agenda, according to two Jackson advisers quoted by political scientist Adolph Reed Jr.

Despite this record, some on the Left, including organizations like the National Committee for Independent Political Action, viewed the Rainbow Coalition as offering a “mass base” of the oppressed to form a possible third party.

But a Rainbow Coalition break from the Democrats was a highly unlikely proposition, no matter how disdainfully the party treated Jackson and the NRC. As Jackson explained at the 1986 conference that transformed Jackson’s campaign into an ongoing organization, “We have too much invested in the Democratic Party. When you have money in the bank you don’t walk away from it.”

In essence, Jackson and the Rainbow Coalition strategy accepted their status as a liberal caucus in a Democratic Party moving rapidly rightward.

After giving the party establishment a little discomfort in 1984, the Jackson campaign took a different tack as the 1988 election season got underway. Jackson opened the race with a much higher level of support. Rather than running an “insurgent” campaign, Jackson focused on a mainstream strategy based on gaining the support of the black Democratic establishment.

Paul Hockenos, writing in the left-wing Guardian newspaper of the era, noted that during the 1988 February New Hampshire primary: “In contrast to 1984, when elected officials and community leaders virtually ignored Jackson, the campaign boasts an impressive list of mainstream endorsements, including Chamber of Commerce officials, four state legislators . . .  and the state president of the Association for the Elderly, among others.”

In November 1987 Jackson appointed black California Assembly Speaker Willie Brown, one of the most powerful politicians in California, to be chairman of his campaign. Brown insisted that the Jackson campaign would not “appeal excessively to so-called black concerns.” With experienced Democratic hands in charge of the campaign, it was more difficult than ever to distinguish Jackson’s “movement” from any other mainstream Democratic campaign.

After his victory in the 1988 Michigan primary, Jackson dropped references in speeches to his “poor campaign with a rich message.” This was because he had begun to attract support from rich donors and big business. Figures released in April 1988 showed that the Jackson camp pulled in some $2 million in March, only $400,000 short of the eventual Democratic presidential nominee, Massachusetts Gov. Michael Dukakis.

Nevertheless, big victories in the California and New Jersey primaries gave Dukakis, a dull technocrat, more than enough delegates to lock up the presidential nomination ahead of the July convention in Atlanta. With more than six hundred “superdelegates” — party officials and politicians chosen by the Democratic establishment to assure the selection of an “electable” candidate — committed to him, Dukakis wrapped up the nomination on the first ballot.

Jackson’s forces arrived at the Atlanta convention with much fanfare. But within days of the convention’s opening, Jackson pledged his support for the Dukakis–Lloyd Bentsen ticket in exchange for representation of several of his advisers (including his son) on the Democratic National Committee and in the general election campaign.

Any hope that he would bring a progressive influence to the party platform was quashed for the sake of “unity.” Jackson agreed to withdraw or water down some of his progressive platform planks, and the Dukakis forces were strong enough to soundly defeat three other Jackson proposals calling for increased taxes on the rich and “no first use” of nuclear weapons.

There should never have been any doubt that Jackson would deliver his supporters to Dukakis in the end. That was the whole aim of the operation: Jackson traded his delegates for his own acceptance into the party’s inner circle. In the spirit of party unity, Jackson’s address to the convention endorsed the demands of party conservatives.

Activists who gave so much energy to nominate Jackson then faced the choice of voting for the conservative ticket that Jackson endorsed — a stark illustration of the ultimate problem with the Rainbow Coalition strategy. From the start, the NRC only succeeded in binding activists to the big business interests that really control the Democratic Party.

Despite appearances to the contrary, Jackson’s presidential campaigns weren’t grassroots efforts. If they had been, the NRC would have built independently of the presidential campaigns. But this wasn’t the case, and the NRC withered as all its resources were plowed into Jackson’s election efforts.

Activists who joined the Rainbow Coalition with the aim of building an “independent” Rainbow distinct from Jackson’s Democratic Party campaign found their hopes dashed. Some broke away and tried to focus on other political activity, including independent political campaigns. But many more were absorbed into the Democratic Party. That included sections of the radical left — in particular, Maoist organizations that counted memberships in the thousands in the early 1970s, only to disintegrate during the conservative era that followed.

While many people today might consider this thirty- and fifty-year-old history to have little relevance, it’s worth noting that much of what is being said on the Left today about Bernie Sanders’ presidential campaign was said about Jackson’s campaigns in the 1980s. For those who would like a more contemporary example, consider how the string of campaigns of former Ohio Rep. Dennis Kucinich disappointed left supporters.

Both Jackson and Kucinich ultimately delivered supporters to the more conservative Democrats against whom they had mounted their challenges in the first place. They did this so effectively and seamlessly that it must be said their campaigns aimed to do this from the start.

Candidates like Jackson or Kucinich occasionally flirted with the rhetoric of breaking with the Democrats, but their clear commitment in practice was to bring people disenchanted with the party into the Democratic orbit. And meanwhile, Sanders, for his part, won’t even use the rhetoric — he has ruled out running outside the Democratic Party. History teaches us that the real impact of these inside-outside challenges was to, in the words of Jesse Jackson, “keep hope alive” — but in the Democratic Party.

For those who want to build a stronger left in the US, there is no substitute for the work — however slow and painstaking it might be — of building social movements and struggles at the grassroots and of organizing a political alternative independent of the Democratic Party.